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How to use the Casio fx-300ES PLUS

The Casio fx-300ES PLUS is a scientific calculator used in many school math and science classes. Its Natural display shows fractions, roots and π as they look in a textbook.

This page has a working practice keypad, a plain guide to every key, and short lessons. They cover fractions, the S⇔D key, standard deviation, lines of best fit, tables, nCr, powers, roots and logs.

Everything follows CASIO's own User's Guide for the calculator, written in our own words. Calcapedia is independent of CASIO.

Lessons: learn the Casio fx-300ES PLUS step by step

0 of 13 done

  1. Fractions and mixed numbersType fractions and mixed numbers, add them, and switch the answer between mixed and improper.

    Step by step

    1. □/□5▼8

      Press the fraction key, type the top number 5, press ▼, then type the bottom number 8.

      Display: 5/8 (our simulation; the guidebook doesn't show this screen)

    2. ►+SHIFT[□□/□]2►1▼4

      Press ► to leave the fraction, then +. SHIFT [□□/□] opens a mixed number: type 2, press ►, then 1, ▼ and 4.

      Display: 5/8+2 1/4 (our simulation; the guidebook doesn't show this screen)

    3. =

      Press =. The answer is an improper fraction in lowest terms.

      Display: 23/8

    4. SHIFT[ab/c⇔d/c]

      Press SHIFT, then [ab/c⇔d/c] (the S⇔D key), to see it as a mixed number.

      Display: 2 7/8

    5. S⇔D

      Press S⇔D to see the same answer as a decimal.

      Display: 2.875

    Tips

    • Anything you type before pressing ► stays inside the fraction.
    • Type a number first, then the fraction key, and that number becomes the top: 5 □/□ 8 is 5/8 too.

    Use it on a real problem: Fraction Calculator · Mixed Number Converter

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 17, 20–22), in our own words, replayed on this site's simulation.

  2. The S⇔D key and repeating decimalsSwitch an answer between a fraction, a repeating decimal and an ordinary decimal.

    Step by step

    1. □/□5▼11=

      Type 5/11 with the fraction key and press =. The answer stays a fraction.

      Display: 5/11

    2. S⇔D

      Press S⇔D. The line over 4 and 5 means those digits repeat for ever.

      Display: 0.4̅5̅

    3. S⇔D

      Press S⇔D again for the ordinary decimal, rounded to fit the screen.

      Display: 0.4545454545

    4. S⇔D

      One more press goes back to the fraction.

      Display: 5/11

    Tips

    • SHIFT then = gives the decimal straight away.
    • A decimal that ends, such as 3/8 = 0.375, has no repeating form, so S⇔D goes straight between 3/8 and 0.375.

    Use it on a real problem: Fraction Calculator · Scientific Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 20–21, 25–29), in our own words, replayed on this site's simulation.

  3. Negative numbers: (−) is not −Type a negative number with (−), and use brackets to square it.

    Step by step

    1. (−)4x²=

      Press (−), 4, x² and =. The calculator squares 4 first, then applies the minus sign.

      Display: -16

    2. ((−)4)x²=

      Put the negative number in brackets: (, (−), 4, ), then x² and =. Now the whole −4 is squared.

      Display: 16

    Tips

    • (−) makes a number negative. − subtracts, so it needs a number before it.
    • When a negative number is raised to a power, put it in brackets.

    Use it on a real problem: Exponent Calculator · Scientific Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 37, 57–58), in our own words, replayed on this site's simulation.

  4. Keep going from the last answer, or fix itUse the last answer in the next calculation, and edit a calculation after pressing =.

    Step by step

    1. 25×4=

      Work out 25 × 4 and press =.

      Display: 100

    2. ÷5

      Press ÷ straight away. The calculator puts Ans, the last answer, in front of it.

      Display: Ans÷5 (our simulation; the guidebook doesn't show this screen)

    3. =

      Press = to divide the last answer by 5.

      Display: 20

    4. 36+14=

      Now work out 36 + 14.

      Display: 50

    5. ◄

      Say you meant 36 + 15. Press ◄: the calculation comes back with the cursor at its end.

      Display: 36+14 (our simulation; the guidebook doesn't show this screen)

    6. DEL5=

      Press DEL to remove the 4, type 5 and press =.

      Display: 51

    Tips

    • Ans puts the last answer anywhere in a calculation, not only at the start.
    • Pressing = again repeats the last calculation with the new answer.
    • ▲ scrolls back to earlier results.

    Use it on a real problem: Percentage Calculator · Average Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 19, 30–32), in our own words, replayed on this site's simulation.

  5. Store a value in A and keep a running total in MSave a number in the variable A, use it later, and add up values in the memory M.

    Step by step

    1. 12×5SHIFT[STO](−)

      Work out 12 × 5 and store it: SHIFT, [STO] (the RCL key), then (−), which stands for A.

      Display: 60

    2. ALPHA[A]÷4=

      Use it: ALPHA, then [A] (the (−) key), ÷ 4 and =.

      Display: 15

    3. RCL(−)

      Press RCL, then (−), to see what A holds.

      Display: 60

    Tips

    • M shows on the screen while M holds anything other than 0.
    • Memories stay when you press AC or switch the calculator off.

    Use it on a real problem: Average Calculator · Scientific Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 33–34), in our own words, replayed on this site's simulation.

  6. Setup: degrees and decimal placesChoose degrees for angles and a fixed number of decimal places, then go back.

    Step by step

    1. SHIFT[SETUP]

      Press SHIFT, then [SETUP] (the MODE key). Each setting has a number.

      Display: 1:MthIO 2:LineIO 3:Deg 4:Rad 5:Gra 6:Fix 7:Sci 8:Norm

    2. 3

      Press 3 for Deg, so angles are read in degrees.

      Display: ▮ (our simulation; the guidebook doesn't show this screen)

    3. sin40)=

      Work out sin 40°.

      Display: 0.6427876097

    4. SHIFT[SETUP]62

      Press SHIFT [SETUP] 6 for Fix, then 2 for two decimal places.

      Display: ▮ (our simulation; the guidebook doesn't show this screen)

    5. sin40)=

      Work out sin 40° again: the answer is rounded to two places.

      Display: 0.64

    6. SHIFT[SETUP]81

      Press SHIFT [SETUP] 8 1 to go back to Norm 1, the usual format.

      Display: ▮ (our simulation; the guidebook doesn't show this screen)

    Tips

    • D at the top of the screen means degrees and R means radians.
    • Fix rounds only what you see; the calculator keeps the full value.
    • SHIFT 9 (CLR) 1 = puts every setting back to how it started.

    Use it on a real problem: Trigonometry Calculator · Scientific Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 10–12, 14–15, 35), in our own words, replayed on this site's simulation.

  7. Standard deviation in the STAT modeEnter a list of numbers and find its standard deviation and mean.

    Step by step

    1. MODE2

      Press MODE, then 2 for STAT. A list of statistics types opens.

      Display: 1:1-VAR 2:A+BX 3:_+CX² 4:ln X 5:e^X 6:A•B^X 7:A•X^B 8:1/X

    2. 1

      Press 1 for 1-VAR, one list of numbers. The data editor opens.

      Display: X1= (our simulation; the guidebook doesn't show this screen)

    3. 4=7=9=10=15=

      Type each value and press = after it: 4, 7, 9, 10 and 15.

      Display: X6= (our simulation; the guidebook doesn't show this screen)

    4. AC

      Press AC to leave the editor. Your data is kept.

      Display: ▮ (our simulation; the guidebook doesn't show this screen)

    5. SHIFT[STAT]4

      Press SHIFT, then [STAT] (the 1 key), then 4 for Var.

      Display: 1:n 2:x̄ 3:σx 4:sx

    6. 3=

      Press 3 for σx, the population standard deviation, then =.

      Display: 3.633180425

    7. ACSHIFT[STAT]44=

      Do it again with 4 for sx, the sample standard deviation.

      Display: 4.062019202

    8. ACSHIFT[STAT]42=

      And with 2 for x̄, the mean.

      Display: 9

    Tips

    • Use sx for a sample and σx when your list is the whole group.
    • MODE 1 takes you back to ordinary sums. Leaving STAT deletes the list.

    Use it on a real problem: Standard Deviation Calculator · Average Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 43–47), in our own words, replayed on this site's simulation.

  8. Line of best fit with A+BXEnter paired data and find the line y = A + Bx and its correlation r.

    Step by step

    1. MODE22

      Press MODE 2 for STAT, then 2 for A+BX, a straight line.

      Display: X1= (our simulation; the guidebook doesn't show this screen)

    2. 2=3=5=8=

      Type the x values, each with =: 2, 3, 5 and 8.

      Display: X5= (our simulation; the guidebook doesn't show this screen)

    3. ▲▲▲▲►

      Press ▲ four times to go back to the first row, then ► for the Y column.

      Display: Y1=0 (our simulation; the guidebook doesn't show this screen)

    4. 11=14=19=27=

      Type the y values, each with =: 11, 14, 19 and 27.

      Display: Y5= (our simulation; the guidebook doesn't show this screen)

    5. ACSHIFT[STAT]5

      Press AC, then SHIFT [STAT] and 5 for Reg.

      Display: 1:A 2:B 3:r 4:x̂ 5:ŷ

    6. 1=

      Press 1 for A, where the line crosses the y axis, then =.

      Display: 5.857142857

    7. ACSHIFT[STAT]52=

      Do it again with 2 for B, the slope.

      Display: 2.642857143

    8. ACSHIFT[STAT]53=

      And with 3 for r. Close to 1 means the points sit close to a rising line.

      Display: 0.9997566022

    Tips

    • The line is y = A + Bx, so A is the starting value and B the slope.
    • ŷ in the Reg menu predicts y for an x you type before it.

    Use it on a real problem: Linear Regression Calculator · Slope Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 43–45, 48–49), in our own words, replayed on this site's simulation.

  9. Combinations, permutations and factorialsCount choices with nCr and nPr, and work out a factorial with x!.

    Step by step

    1. 10SHIFT[nCr]3=

      Ways to pick 3 of 10 toppings, order not mattering: 10, SHIFT [nCr] (the ÷ key), 3, =.

      Display: 120

    2. AC10SHIFT[nPr]3=

      Ways to give gold, silver and bronze to 3 of 10 runners: 10, SHIFT [nPr] (the × key), 3, =.

      Display: 720

    3. AC5SHIFT[x!]=

      Ways to line up 5 people: 5, SHIFT [x!] (the x⁻¹ key), =.

      Display: 120

    Tips

    • Use nCr when order doesn't matter and nPr when it does.
    • Type the bigger number first.

    Use it on a real problem: Combination Calculator · Permutation Calculator · Factorial Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 39–41), in our own words, replayed on this site's simulation.

  10. Scientific notation with ×10ˣ and SciType numbers in scientific notation and show answers that way.

    Step by step

    1. 3.2×10ˣ5×4×10ˣ(−)3=

      Type 3.2, ×10ˣ, 5 for 3.2×10⁵. Then × 4 ×10ˣ (−) 3 for 4×10⁻³, and =.

      Display: 1280

    2. SHIFT[SETUP]73

      To see answers in scientific notation, press SHIFT [SETUP] 7 for Sci, then 3 significant digits.

      Display: ▮ (our simulation; the guidebook doesn't show this screen)

    3. 1280=

      Type 1280 and press =.

      Display: 1.28×10³

    4. SHIFT[SETUP]81

      Press SHIFT [SETUP] 8 1 to go back to Norm 1.

      Display: ▮ (our simulation; the guidebook doesn't show this screen)

    Tips

    • Use (−) for a negative power, not the − key.
    • ×10ˣ belongs to the number before it, so you don't need brackets.
    • ENG shows the answer with a power of ten that is a multiple of 3.

    Use it on a real problem: Scientific Notation Calculator · Exponent Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 12, 23), in our own words, replayed on this site's simulation.

  11. A table of values in the TABLE modeType a function and list its values for a range of x.

    Step by step

    1. MODE3

      Press MODE, then 3 for TABLE.

      Display: f(X)= (our simulation; the guidebook doesn't show this screen)

    2. ALPHA[X]x²−2ALPHA[X]

      Type x² − 2x. X is ALPHA [X], the ) key.

      Display: f(X)=X²-2X (our simulation; the guidebook doesn't show this screen)

    3. =

      Press =. The calculator asks for a second function, g(X).

      Display: g(X)= (our simulation; the guidebook doesn't show this screen)

    4. =

      Press = again to skip g(X).

      Display: Start?1

    5. 0=

      Type 0 for the first x and press =.

      Display: End?5

    6. 4=

      Type 4 for the last x and press =.

      Display: Step?1

    7. 1=

      Press 1 = to go up by 1 each row. The table opens.

      Display: X=0,F(X)=0 (our simulation; the guidebook doesn't show this screen)

    8. ▼

      Press ▼ to go down the table.

      Display: X=1,F(X)=-1 (our simulation; the guidebook doesn't show this screen)

    9. ▼▼▼

      Keep pressing ▼ to see the rest.

      Display: X=4,F(X)=8 (our simulation; the guidebook doesn't show this screen)

    Tips

    • AC goes back to the function, so you can change it.
    • A table can have up to 20 rows. Choosing f(x) only in the setup allows 30.
    • MODE 1 goes back to ordinary sums.

    Use it on a real problem: Parabola Calculator · Slope Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 51–53), in our own words, replayed on this site's simulation.

  12. Powers and rootsRaise a number to any power and take square, cube and other roots.

    Step by step

    1. 2x■10=

      Type 2, press the power key x■, then 10 for 2 to the 10th.

      Display: 1024

    2. ACSHIFT[∛]343=

      Press SHIFT [∛] (the √ key), type 343 and press = for its cube root.

      Display: 7

    3. ACSHIFT[ˣ√]4►81=

      Press SHIFT [ˣ√] (the x■ key). Type 4 for a 4th root, press ►, then 81 and =.

      Display: 3

    4. AC√200=

      Press √, type 200 and press =. The answer is a simplified root.

      Display: 10√2

    5. S⇔D

      Press S⇔D to see it as a decimal.

      Display: 14.14213562

    Tips

    • x² and x³ square and cube with one key.
    • Press ► to leave a power or root before typing more.

    Use it on a real problem: Square Root Calculator · Exponent Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 17, 20, 37–38), in our own words, replayed on this site's simulation.

  13. Logarithms, including any baseWork out log, ln and a logarithm to any base.

    Step by step

    1. log1000)=

      Press log, type 1000, close the bracket and press =. This is the log to base 10.

      Display: 3

    2. ACln20)=

      Press ln, type 20, close the bracket and press = for the natural log.

      Display: 2.995732274

    3. AClog■□3►81=

      For any base, press log■□. Type the base 3, press ►, type 81 and press =.

      Display: 4

    Tips

    • The answer is the power: 3⁴ = 81, so the log of 81 to base 3 is 4.
    • SHIFT log gives 10 to a power, and SHIFT ln gives e to a power.

    Use it on a real problem: Logarithm Calculator · Exponent Calculator

    Keys follow fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide (pp. 36), in our own words, replayed on this site's simulation.

D · Math

Display: ▮

SHIFTMakes the next key do the function printed above it on the left; S shows on the screen. Pressing SHIFT again cancels it.ALPHAMakes the next key type the letter or name printed above it on the right, such as the variable A; A shows on the screen.MODEOpens the mode menu: 1 COMP for everyday calculations, 2 STAT for statistics, 3 TABLE for a table of values. Changing the mode clears the history.ONTurns the calculator on. Memories, Ans and the variables are kept while it is off.
◄Moves the cursor left, out of a denominator and out of a template. At the start of a line it jumps to the end. After an answer it opens that calculation for editing; after an error, it puts the cursor where the error is.▲Scrolls back through earlier results. In a fraction, moves up to the numerator; in Linear display, jumps to the start of the line.▼Moves from a numerator down to its denominator, and forward through the history. It also turns to the second setup screen.►Moves the cursor right: from a numerator to its denominator, and out of a denominator, root or power. At the end of a line it jumps to the start. After an error, it puts the cursor where the error is.
AbsAbsolute value: in Natural display it opens |□|, in Linear display it types Abs(. SHIFT Abs is ÷R.x³Cubes the value before it. ALPHA x³ types the colon that joins statements.x⁻¹The reciprocal of the value before it: 4 x⁻¹ is 1/4. SHIFT x⁻¹ is x!.log■□Opens log with a box for the base, then ► moves to the number: log₂16 is 4. Natural display only.
□/□Opens a fraction. Keyed after a number, that number becomes the numerator and the cursor goes to the denominator. In Linear display it types the ┘ mark.√Opens a square root; what follows goes under it until ►.x²Squares the value before it. It can't follow another power key straight away.x■Raises the value before it to a power typed in the raised box; ► leaves the box.logTypes log(. With one number the base is 10; log(a,b), with SHIFT ) as the comma, is the log of b to base a. SHIFT log is 10■.lnNatural logarithm, to base e. SHIFT ln is e■, e to a power.(−)Makes the next number negative. It is not the − key, which subtracts. After STO or RCL it means the variable A.°′″Marks degrees, minutes and seconds as you type them: 2 °′″ 15 °′″ 18 °′″. After an answer it switches between sexagesimal and decimal.hypOpens the hyperbolic menu: 1 sinh, 2 cosh, 3 tanh, then their inverses at 4 to 6. The angle unit doesn't affect them.sinSine of the angle after it, in the unit set on the setup screen. It opens a bracket that ) closes.cosCosine of the angle after it, in the current angle unit.tanTangent of the angle after it, in the current angle unit.RCLShows what a variable holds: RCL then the variable's key, such as (−) for A, sin for D or M+ for M.ENGShows the answer with a power of ten that is a multiple of 3. Each press moves the point right; SHIFT ENG moves it left.(Opens a bracket. SHIFT ( is %.)Closes a bracket. SHIFT ) is the comma between two values; ALPHA ) is the variable X.S⇔DSwitches the answer on the screen between its fraction, root or π form and its decimal. With Rdec on, a fraction also shows as a recurring decimal on the way.M+Works out the line, or takes the answer shown, and adds it to the memory M. M shows on the screen while M isn't 0.
7The number 7.8The number 8.9The number 9.DELDeletes what is just to the left of the cursor. In the Statistics Editor, it deletes the row the cursor is on.ACClears the line you are typing. On an error message, it clears the message and the calculation. It also closes menus.4The number 4.5The number 5.6The number 6.×Multiply. SHIFT × is nPr (permutations); ALPHA × is GCD.÷Divide. SHIFT ÷ is nCr (combinations); ALPHA ÷ is LCM.1The number 1.2The number 2.3The number 3.+Add. SHIFT + is Pol (rectangular to polar); ALPHA + is Int.−Subtract. SHIFT − is Rec (polar to rectangular); ALPHA − is Intg.0The number 0..The decimal point. SHIFT . is Ran#, a random number; ALPHA . is RanInt#.×10ˣKeys a power of ten into a number: 3 ×10ˣ 8 is 3×10⁸, and (−) makes the power negative. SHIFT ×10ˣ is π and ALPHA ×10ˣ is e.AnsTypes Ans, the last answer, into the calculation.=Works out the answer. Pressed again, it repeats the last calculation; SHIFT then = gives the answer as a decimal.
[SETUP] (second function)Opens the setup screens: display format, angle unit, number format, then (▼) fractions, statistics frequency and recurring decimals. A number key picks a setting.[OFF] (second function)Turns the calculator off. Press ON to turn it back on.[÷R] (second function)Divides and gives the remainder too: 5 ÷R 2 shows 2,R=1. Ans keeps only the quotient.[x!] (second function)Factorial of the whole number before it, from 0 to 69: (5 + 3)! is 40320.[□□/□] (second function)Opens a mixed fraction with the cursor on the whole-number part; ► moves on to the numerator. Keyed after a number, that number becomes the whole-number part.[∛] (second function)Cube root. In Natural display it opens a template; in Linear display it types ∛( for ) to close.[ˣ√] (second function)A root of any index. In Natural display key the index, ►, then the number; in Linear display key the index first.[10■] (second function)Ten to the power typed in the raised box.[e■] (second function)e to the power typed in the raised box: e⁵ × 2 is about 296.8.[FACT] (second function)Shows a whole-number answer as prime factors, such as 2×3×13². = or SHIFT FACT goes back. COMP mode only.[sin⁻¹] (second function)The angle whose sine is the number after it, in the current angle unit.[cos⁻¹] (second function)The angle whose cosine is the number after it.[tan⁻¹] (second function)The angle whose tangent is the number after it.[STO] (second function)Works out the line, or takes the answer shown, and stores it in the variable keyed next. The keys are (−) A, °′″ B, hyp C, sin D, cos E, tan F, ) X, S⇔D Y and M+ M.[←] (second function)Engineering notation with the decimal point moved left: 123 becomes 0.123×10³.[%] (second function)Keyed after a value, divides it by 100: 150 × 20 % is 30.[,] (second function)The comma between two values, as in log(2,16), Pol(x,y) and GCD(28,35).[ab/c⇔d/c] (second function)Switches a fraction answer between a mixed fraction and an improper one.[M−] (second function)Works out the line, or takes the answer shown, and subtracts it from M.[CLR] (second function)Resets the setup, clears the memories, or both; press = to confirm.[INS] (second function)In Natural display, the next function, such as √, takes what is right of the cursor. In Linear display it switches insert and overwrite.[nPr] (second function)Permutations: 10 nPr 4 is 5040, the ordered ways to pick 4 of 10.[nCr] (second function)Combinations: 10 nCr 4 is 210, the ways to pick 4 of 10 when order doesn't matter.[STAT] (second function)In the STAT mode, opens the statistics menu: Type, Data, Sum, Var, MinMax and, for paired data, Reg with A, B, r and the estimates x̂ and ŷ.[Pol] (second function)Rectangular to polar: Pol(x,y) shows r and θ and stores them in X and Y.[Rec] (second function)Polar to rectangular: Rec(r,θ) shows x and y and stores them in X and Y.[Rnd] (second function)Rounds the value in brackets to the digits the display shows, so Rnd(10÷3)×3 is 9.999 under Fix 3.[Ran#] (second function)A random number from 0.000 to 0.999. This keypad has its own random sequence, so its numbers differ from a real calculator's.[π] (second function)Pi. In Natural display answers keep it exact, such as (1/6)π.[DRG►] (second function)Opens the angle-unit menu: 1 ° (degrees), 2 ʳ (radians), 3 ᵍ (grads). After a value, it converts that value to the current unit.
[:] (second function)Joins statements on one line: = works out the first, and each = after that the next.[‾] (second function)Starts the repeating part of a decimal, after the point: 0 . ‾ 3 is 0.333…. Natural display only.[A] (second function)Types the variable A into the calculation.[B] (second function)Types the variable B into the calculation.[C] (second function)Types the variable C into the calculation.[D] (second function)Types the variable D into the calculation.[E] (second function)Types the variable E into the calculation.[F] (second function)Types the variable F into the calculation.[X] (second function)Types the variable X into the calculation.[Y] (second function)Types the variable Y into the calculation. Pol and Rec store their second result here.[M] (second function)Types M, the independent memory, into the calculation.[GCD] (second function)Greatest common divisor of two whole numbers: GCD(28,35) is 7.[LCM] (second function)Least common multiple of two whole numbers: LCM(9,15) is 45.[Int] (second function)The whole-number part, towards zero: Int(−3.5) is −3.[Intg] (second function)The largest whole number not above the value: Intg(−3.5) is −4.[RanInt] (second function)A random whole number from a to b, as RanInt#(1,6). This keypad's numbers differ from a real calculator's.[e] (second function)e, the base of natural logarithms, about 2.718281828.[PreAns] (second function)Types PreAns, the answer before the last one. COMP mode only.

It works! Press the keys to calculate. Hover over or tab to a key to see what it does.

What every key on the Casio fx-300ES PLUS does

A scientific calculator with Natural display: fractions, roots and π shown as in a textbook, plus quick statistics.

What every key does (89)

Control keys

SHIFT
Makes the next key do the function printed above it on the left; S shows on the screen. Pressing SHIFT again cancels it.
ALPHA
Makes the next key type the letter or name printed above it on the right, such as the variable A; A shows on the screen.
MODE
Opens the mode menu: 1 COMP for everyday calculations, 2 STAT for statistics, 3 TABLE for a table of values. Changing the mode clears the history.
ON
Turns the calculator on. Memories, Ans and the variables are kept while it is off.

Arrow keys

◄
Moves the cursor left, out of a denominator and out of a template. At the start of a line it jumps to the end. After an answer it opens that calculation for editing; after an error, it puts the cursor where the error is.
▲
Scrolls back through earlier results. In a fraction, moves up to the numerator; in Linear display, jumps to the start of the line.
▼
Moves from a numerator down to its denominator, and forward through the history. It also turns to the second setup screen.
►
Moves the cursor right: from a numerator to its denominator, and out of a denominator, root or power. At the end of a line it jumps to the start. After an error, it puts the cursor where the error is.

Keys beside the arrows

Abs
Absolute value: in Natural display it opens |□|, in Linear display it types Abs(. SHIFT Abs is ÷R.
x³
Cubes the value before it. ALPHA x³ types the colon that joins statements.
x⁻¹
The reciprocal of the value before it: 4 x⁻¹ is 1/4. SHIFT x⁻¹ is x!.
log■□
Opens log with a box for the base, then ► moves to the number: log₂16 is 4. Natural display only.

Function keys

□/□
Opens a fraction. Keyed after a number, that number becomes the numerator and the cursor goes to the denominator. In Linear display it types the ┘ mark.
√
Opens a square root; what follows goes under it until ►.
x²
Squares the value before it. It can't follow another power key straight away.
x■
Raises the value before it to a power typed in the raised box; ► leaves the box.
log
Types log(. With one number the base is 10; log(a,b), with SHIFT ) as the comma, is the log of b to base a. SHIFT log is 10■.
ln
Natural logarithm, to base e. SHIFT ln is e■, e to a power.
(−)
Makes the next number negative. It is not the − key, which subtracts. After STO or RCL it means the variable A.
°′″
Marks degrees, minutes and seconds as you type them: 2 °′″ 15 °′″ 18 °′″. After an answer it switches between sexagesimal and decimal.
hyp
Opens the hyperbolic menu: 1 sinh, 2 cosh, 3 tanh, then their inverses at 4 to 6. The angle unit doesn't affect them.
sin
Sine of the angle after it, in the unit set on the setup screen. It opens a bracket that ) closes.
cos
Cosine of the angle after it, in the current angle unit.
tan
Tangent of the angle after it, in the current angle unit.
RCL
Shows what a variable holds: RCL then the variable's key, such as (−) for A, sin for D or M+ for M.
ENG
Shows the answer with a power of ten that is a multiple of 3. Each press moves the point right; SHIFT ENG moves it left.
(
Opens a bracket. SHIFT ( is %.
)
Closes a bracket. SHIFT ) is the comma between two values; ALPHA ) is the variable X.
S⇔D
Switches the answer on the screen between its fraction, root or π form and its decimal. With Rdec on, a fraction also shows as a recurring decimal on the way.
M+
Works out the line, or takes the answer shown, and adds it to the memory M. M shows on the screen while M isn't 0.

Number keys

0–9
The number keys. Type numbers the way you write them.
DEL
Deletes what is just to the left of the cursor. In the Statistics Editor, it deletes the row the cursor is on.
AC
Clears the line you are typing. On an error message, it clears the message and the calculation. It also closes menus.
×
Multiply. SHIFT × is nPr (permutations); ALPHA × is GCD.
÷
Divide. SHIFT ÷ is nCr (combinations); ALPHA ÷ is LCM.
+
Add. SHIFT + is Pol (rectangular to polar); ALPHA + is Int.
−
Subtract. SHIFT − is Rec (polar to rectangular); ALPHA − is Intg.
.
The decimal point. SHIFT . is Ran#, a random number; ALPHA . is RanInt#.
×10ˣ
Keys a power of ten into a number: 3 ×10ˣ 8 is 3×10⁸, and (−) makes the power negative. SHIFT ×10ˣ is π and ALPHA ×10ˣ is e.
Ans
Types Ans, the last answer, into the calculation.
=
Works out the answer. Pressed again, it repeats the last calculation; SHIFT then = gives the answer as a decimal.

SHIFT functions (press SHIFT first)

[SETUP]
Second function: press 2nd first. Opens the setup screens: display format, angle unit, number format, then (▼) fractions, statistics frequency and recurring decimals. A number key picks a setting.
[OFF]
Second function: press 2nd first. Turns the calculator off. Press ON to turn it back on.
[÷R]
Second function: press 2nd first. Divides and gives the remainder too: 5 ÷R 2 shows 2,R=1. Ans keeps only the quotient.
[x!]
Second function: press 2nd first. Factorial of the whole number before it, from 0 to 69: (5 + 3)! is 40320.
[□□/□]
Second function: press 2nd first. Opens a mixed fraction with the cursor on the whole-number part; ► moves on to the numerator. Keyed after a number, that number becomes the whole-number part.
[∛]
Second function: press 2nd first. Cube root. In Natural display it opens a template; in Linear display it types ∛( for ) to close.
[ˣ√]
Second function: press 2nd first. A root of any index. In Natural display key the index, ►, then the number; in Linear display key the index first.
[10■]
Second function: press 2nd first. Ten to the power typed in the raised box.
[e■]
Second function: press 2nd first. e to the power typed in the raised box: e⁵ × 2 is about 296.8.
[FACT]
Second function: press 2nd first. Shows a whole-number answer as prime factors, such as 2×3×13². = or SHIFT FACT goes back. COMP mode only.
[sin⁻¹]
Second function: press 2nd first. The angle whose sine is the number after it, in the current angle unit.
[cos⁻¹]
Second function: press 2nd first. The angle whose cosine is the number after it.
[tan⁻¹]
Second function: press 2nd first. The angle whose tangent is the number after it.
[STO]
Second function: press 2nd first. Works out the line, or takes the answer shown, and stores it in the variable keyed next. The keys are (−) A, °′″ B, hyp C, sin D, cos E, tan F, ) X, S⇔D Y and M+ M.
[←]
Second function: press 2nd first. Engineering notation with the decimal point moved left: 123 becomes 0.123×10³.
[%]
Second function: press 2nd first. Keyed after a value, divides it by 100: 150 × 20 % is 30.
[,]
Second function: press 2nd first. The comma between two values, as in log(2,16), Pol(x,y) and GCD(28,35).
[ab/c⇔d/c]
Second function: press 2nd first. Switches a fraction answer between a mixed fraction and an improper one.
[M−]
Second function: press 2nd first. Works out the line, or takes the answer shown, and subtracts it from M.
[CLR]
Second function: press 2nd first. Resets the setup, clears the memories, or both; press = to confirm.
[INS]
Second function: press 2nd first. In Natural display, the next function, such as √, takes what is right of the cursor. In Linear display it switches insert and overwrite.
[nPr]
Second function: press 2nd first. Permutations: 10 nPr 4 is 5040, the ordered ways to pick 4 of 10.
[nCr]
Second function: press 2nd first. Combinations: 10 nCr 4 is 210, the ways to pick 4 of 10 when order doesn't matter.
[STAT]
Second function: press 2nd first. In the STAT mode, opens the statistics menu: Type, Data, Sum, Var, MinMax and, for paired data, Reg with A, B, r and the estimates x̂ and ŷ.
[Pol]
Second function: press 2nd first. Rectangular to polar: Pol(x,y) shows r and θ and stores them in X and Y.
[Rec]
Second function: press 2nd first. Polar to rectangular: Rec(r,θ) shows x and y and stores them in X and Y.
[Rnd]
Second function: press 2nd first. Rounds the value in brackets to the digits the display shows, so Rnd(10÷3)×3 is 9.999 under Fix 3.
[Ran#]
Second function: press 2nd first. A random number from 0.000 to 0.999. This keypad has its own random sequence, so its numbers differ from a real calculator's.
[π]
Second function: press 2nd first. Pi. In Natural display answers keep it exact, such as (1/6)π.
[DRG►]
Second function: press 2nd first. Opens the angle-unit menu: 1 ° (degrees), 2 ʳ (radians), 3 ᵍ (grads). After a value, it converts that value to the current unit.

ALPHA functions (press ALPHA first)

[:]
Second function: press 2nd first. Joins statements on one line: = works out the first, and each = after that the next.
[‾]
Second function: press 2nd first. Starts the repeating part of a decimal, after the point: 0 . ‾ 3 is 0.333…. Natural display only.
[A]
Second function: press 2nd first. Types the variable A into the calculation.
[B]
Second function: press 2nd first. Types the variable B into the calculation.
[C]
Second function: press 2nd first. Types the variable C into the calculation.
[D]
Second function: press 2nd first. Types the variable D into the calculation.
[E]
Second function: press 2nd first. Types the variable E into the calculation.
[F]
Second function: press 2nd first. Types the variable F into the calculation.
[X]
Second function: press 2nd first. Types the variable X into the calculation.
[Y]
Second function: press 2nd first. Types the variable Y into the calculation. Pol and Rec store their second result here.
[M]
Second function: press 2nd first. Types M, the independent memory, into the calculation.
[GCD]
Second function: press 2nd first. Greatest common divisor of two whole numbers: GCD(28,35) is 7.
[LCM]
Second function: press 2nd first. Least common multiple of two whole numbers: LCM(9,15) is 45.
[Int]
Second function: press 2nd first. The whole-number part, towards zero: Int(−3.5) is −3.
[Intg]
Second function: press 2nd first. The largest whole number not above the value: Intg(−3.5) is −4.
[RanInt]
Second function: press 2nd first. A random whole number from a to b, as RanInt#(1,6). This keypad's numbers differ from a real calculator's.
[e]
Second function: press 2nd first. e, the base of natural logarithms, about 2.718281828.
[PreAns]
Second function: press 2nd first. Types PreAns, the answer before the last one. COMP mode only.

Solve real problems on the Casio fx-300ES PLUS

Each calculator page shows the exact keys for its problem on this keypad.

Common questions about the Casio fx-300ES PLUS

How do I change a fraction to a decimal on the Casio fx-300ES PLUS?
With the answer on the screen, press S⇔D. A fraction may show as a repeating decimal first; press S⇔D again for the ordinary decimal.
How do I type a fraction?
Press the fraction key, type the top number, press ▼ and type the bottom number. Press ► to leave the fraction before typing anything else.
Where is the percent key?
% is the SHIFT function of the ( key. Key it after the number: 80 × 15 SHIFT % = gives 12, which is 15% of 80.
How do I set degrees?
Press SHIFT, then MODE for the setup screen, and press 3 for Deg. D shows at the top of the screen while degrees are in use.
Why is my negative number squared still negative?
The calculator squares before it applies the negative sign, so (−) 2 x² gives −4. Put the negative number in brackets to square it.
How do I find standard deviation on the Casio fx-300ES PLUS?
Press MODE 2 1 and type each value with =. Then press AC and SHIFT 1 4 for Var. Pick 3 for σx or 4 for sx, and press =.
How do I find a line of best fit?
Press MODE 2 2 for A+BX and type the x and y columns. Then press AC and SHIFT 1 5 for Reg. A, B and r are items 1, 2 and 3.
How do I make a table of values?
Press MODE 3 and type the function, using ALPHA ) for X. Press = twice, then type Start, End and Step, each with =.
Where are nCr and nPr?
nCr is SHIFT ÷ and nPr is SHIFT ×. Type the bigger number first: 10 SHIFT ÷ 3 = gives 120.

The keypad is Calcapedia's simulation of this calculator, and every lesson is replayed on it automatically. Real calculators can label some keys differently.

Sources: fx-300ES PLUS (2nd edition / NATURAL-V.P.A.M.) User's Guide.

Calcapedia is independent and is not affiliated with or endorsed by CASIO COMPUTER CO., LTD. CASIO and fx-300ES PLUS are trademarks of their owner and are used here only to say which calculator these steps are for.