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LCM worksheet

Grade 6 · CCSS 6.NS.B.4

Solve each problem and show your work. Round answers to 2 decimal places where needed.

1.
Problem 1.
- Whole numbers: 4, 6, 18
Find: Least common multiple
Answer
2.
Problem 2.
- Whole numbers: 3, 6, 13
Find: Least common multiple
Answer
3.
Problem 3.
- Whole numbers: 3, 5, 16
Find: Least common multiple
Answer
4.
Problem 4.
- Whole numbers: 4, 6, 15
Find: Least common multiple
Answer
5.
Problem 5.
- Whole numbers: 5, 8, 13
Find: Least common multiple
Answer
6.
Problem 6.
- Whole numbers: 4, 7, 12
Find: Least common multiple
Answer
7.
Problem 7.
- Whole numbers: 3, 6, 14
Find: Least common multiple
Answer
8.
Problem 8.
- Whole numbers: 6, 5, 16
Find: Least common multiple
Answer
9.
Problem 9.
- Whole numbers: 3, 6, 19
Find: Least common multiple
Answer
10.
Problem 10.
- Whole numbers: 5, 6, 19
Find: Least common multiple
Answer

Answer key: LCM worksheet

1. Least common multiple: 36
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 4 and 6 is 2, so their LCM is their product divided by 2
  $lcm(4, 6)$ $= \frac{4 \times 6}{2}$ $= 12$
3. The GCF of 12 and 18 is 6, so their LCM is their product divided by 6
  $lcm(12, 18)$ $= \frac{12 \times 18}{6}$ $= 36$
2. Least common multiple: 78
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 3 and 6 is 3, so their LCM is their product divided by 3
  $lcm(3, 6)$ $= \frac{3 \times 6}{3}$ $= 6$
3. The GCF of 6 and 13 is 1, so their LCM is their product divided by 1
  $lcm(6, 13)$ $= \frac{6 \times 13}{1}$ $= 78$
3. Least common multiple: 240
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 3 and 5 is 1, so their LCM is their product divided by 1
  $lcm(3, 5)$ $= \frac{3 \times 5}{1}$ $= 15$
3. The GCF of 15 and 16 is 1, so their LCM is their product divided by 1
  $lcm(15, 16)$ $= \frac{15 \times 16}{1}$ $= 240$
4. Least common multiple: 60
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 4 and 6 is 2, so their LCM is their product divided by 2
  $lcm(4, 6)$ $= \frac{4 \times 6}{2}$ $= 12$
3. The GCF of 12 and 15 is 3, so their LCM is their product divided by 3
  $lcm(12, 15)$ $= \frac{12 \times 15}{3}$ $= 60$
5. Least common multiple: 520
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 5 and 8 is 1, so their LCM is their product divided by 1
  $lcm(5, 8)$ $= \frac{5 \times 8}{1}$ $= 40$
3. The GCF of 40 and 13 is 1, so their LCM is their product divided by 1
  $lcm(40, 13)$ $= \frac{40 \times 13}{1}$ $= 520$
6. Least common multiple: 84
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 4 and 7 is 1, so their LCM is their product divided by 1
  $lcm(4, 7)$ $= \frac{4 \times 7}{1}$ $= 28$
3. The GCF of 28 and 12 is 4, so their LCM is their product divided by 4
  $lcm(28, 12)$ $= \frac{28 \times 12}{4}$ $= 84$
7. Least common multiple: 42
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 3 and 6 is 3, so their LCM is their product divided by 3
  $lcm(3, 6)$ $= \frac{3 \times 6}{3}$ $= 6$
3. The GCF of 6 and 14 is 2, so their LCM is their product divided by 2
  $lcm(6, 14)$ $= \frac{6 \times 14}{2}$ $= 42$
8. Least common multiple: 240
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 6 and 5 is 1, so their LCM is their product divided by 1
  $lcm(6, 5)$ $= \frac{6 \times 5}{1}$ $= 30$
3. The GCF of 30 and 16 is 2, so their LCM is their product divided by 2
  $lcm(30, 16)$ $= \frac{30 \times 16}{2}$ $= 240$
9. Least common multiple: 114
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 3 and 6 is 3, so their LCM is their product divided by 3
  $lcm(3, 6)$ $= \frac{3 \times 6}{3}$ $= 6$
3. The GCF of 6 and 19 is 1, so their LCM is their product divided by 1
  $lcm(6, 19)$ $= \frac{6 \times 19}{1}$ $= 114$
10. Least common multiple: 570
1. Combine the numbers two at a time (a and b). Multiply them, then divide by their GCF, the largest number that divides both, so shared factors aren't counted twice
  $lcm(a, b) = |a × b| ÷ gcf(a, b)$
2. The GCF of 5 and 6 is 1, so their LCM is their product divided by 1
  $lcm(5, 6)$ $= \frac{5 \times 6}{1}$ $= 30$
3. The GCF of 30 and 19 is 1, so their LCM is their product divided by 1
  $lcm(30, 19)$ $= \frac{30 \times 19}{1}$ $= 570$