What this calculator does
Add, subtract, multiply and divide, with brackets and a percent key, and see how each answer was worked out. It works like a pocket calculator. The difference is that it reads your whole line using the usual order of operations. So 2 + 3 × 4 gives 14, not 20.
Tap the keys or type on your keyboard. A preview shows the answer as you go. Press = (or Enter) to save the result and see the working underneath. It shows how the calculator read your line and each step it did, in order. If you need powers, roots or trigonometry, the scientific calculator has the same keypad with more keys.
Where it's used
Why this math matters outside the classroom:
- Splitting a bill. Four friends sharing a $72 dinner plus a $12 tip type (72 + 12) ÷ 4 and each pay $21.
- Checking a receipt. A shopper buying 3 notebooks at $2.50 and a $4 pen types 3 × 2.5 + 4 to confirm the $11.50 total.
- Homework answers. Students check order-of-operations problems such as 12 + 8 × (5 − 2) ÷ 4, which equals 18.
- Quick percentages. Someone working out a 15% share of an $80 cost types 80 × 15% and gets 12.
- Unit prices. Comparing a 12-pack for $9 with a 20-pack for $14, a buyer finds 9 ÷ 12 = 0.75 and 14 ÷ 20 = 0.70 dollars per item.
Grade level and standards: Grades 5–6; Common Core State Standards for Mathematics 5.OA.A.1. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Type the calculation or tap the keys, for example 12 + 8 × (5 − 2) ÷ 4.
- Press = or Enter to get the answer. The working panel lists every step.
- After =, press a sign such as × to keep going from the answer, or a digit to start a new calculation.
- Use ⌫ to delete the last character and AC to clear the line. Esc also clears.
What the inputs mean
- Expression
- You can use digits, a decimal point, + − × ÷, brackets and %. On a keyboard, * and x mean ×, / means ÷, and - means −. If you forget a closing bracket at the very end, the calculator adds it for you.
Formula and method
Order: ( ) first, then × and ÷ left to right, then + and − left to right 12 + 8 × (5 − 2) ÷ 4 = 12 + 8 × 3 ÷ 4 = 12 + 24 ÷ 4 = 12 + 6 = 18 x% = x ÷ 100, so 80 × 15% = 80 × 0.15 = 12 50 + 10% = 50 + (10% of 50) = 50 + 5 = 55
The calculator follows the order taught in school, which scientific calculators and spreadsheets use too. Brackets come first. Then multiplication and division, from left to right. Then addition and subtraction, from left to right. Some very simple desk calculators work strictly in the order you press the keys instead. That's why the same keys can give different answers on different machines.
The % key works the way phone and desktop calculators do. After × or ÷, it divides the number before it by 100. So 80 × 15% is 12, which is 15% of 80. After + or −, it takes that percent of the number on the left. So 50 + 10% is 55 (a 10% markup), and 80 − 25% is 60 (a 25% discount).
Worked example
Work out 12 + 8 × (5 − 2) ÷ 4.
- Brackets first: 5 − 2 = 3.
- Multiply: 8 × 3 = 24.
- Divide: 24 ÷ 4 = 6.
- Add last: 12 + 6 = 18.
Result: 12 + 8 × (5 − 2) ÷ 4 = 18. A calculator that works strictly left to right would give 15 for the same keys (12 + 8 = 20, × 3 = 60, ÷ 4 = 15). That's why the order of operations matters.
Understanding the result
The working panel shows your line exactly as the calculator read it, with every step written out. If that isn't what you meant, add brackets. 100 ÷ (4 × 5) is 5, while 100 ÷ 4 × 5 is 125.
Answers show at most 12 digits. That hides the tiny rounding errors that make some computers show 0.1 + 0.2 as 0.30000000000000004. Very large or very small answers switch to E notation, such as 1.5e+20, which means 1.5 with the decimal point moved 20 places right.
Assumptions and limitations
- All arithmetic uses ordinary numbers stored the way computers usually store them (double-precision floating point). That's accurate to about 15 digits.
- × and ÷ rank the same and are worked from left to right. So are + and −.
- % always means 'divide the number before it by 100'.
- There are no powers, roots, trigonometry, logarithms or memory keys. The scientific calculator has those.
- Dividing by zero shows an error instead of a number.
- A calculation can be up to 300 characters long.
Frequently asked questions
Why does 2 + 3 × 4 give 14 and not 20?
Multiplication comes before addition. So the calculator works out 3 × 4 = 12 first, then adds 2. If you want the addition done first, use brackets: (2 + 3) × 4 = 20.
What exactly does the % key do?
After × or ÷, it divides the number just before it by 100. So 80 × 15% is 12, which is 15% of 80. After + or −, it adds or takes off that percent of the number on the left. So 50 + 10% is 55, like on a phone calculator. Some older desk and scientific calculators treat % differently. If a result surprises you, write the percent out: 50 + 50 × 10 ÷ 100.
How do I keep calculating with the answer?
After pressing =, press a sign such as ÷. The calculator starts the next line with your last answer. So 6 × 7 = followed by ÷ 2 = gives 21. Pressing a digit instead starts a brand-new calculation.
Can I use my keyboard?
Yes. Digits, the decimal point, + and - work as they are. * or x multiplies, / divides, and ( and ) are brackets. Enter or = gives the answer, Backspace deletes and Esc clears.
How this calculator is checked
Method: Standard operator precedence and left-to-right associativity from school arithmetic, evaluated by the site's own expression parser; percent is defined as division by 100. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-19. Found a problem? Tell us.
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