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GCF of Two Numbers — Easy Worksheet 1
Grade 6 · Whoobee Name: ____________________ Date: __________
Answer each question. Every one uses the greatest common factor (GCF).
How to solve
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Example
GCF of 6 and 9
Answer: 3
Warm-up
Not quite. The answer is
💡 Factors of 4: 1, 2, 4. Factors of 20: 1, 2, 4, 5, 10, 20. The common factors are 1, 2, 4. The greatest is 4, so the GCF is 4.
✓ Correct!
Not quite. The answer is
💡 Factors of 4: 1, 2, 4. Factors of 20: 1, 2, 4, 5, 10, 20. The common factors are 1, 2, 4. The greatest is 4, so the GCF is 4.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 2 and 12
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Factors of 5: 1, 5. Factors of 10: 1, 2, 5, 10. The common factors are 1, 5. The greatest is 5, so the GCF is 5.
✓ Correct!
Not quite. The answer is
💡 Factors of 5: 1, 5. Factors of 10: 1, 2, 5, 10. The common factors are 1, 5. The greatest is 5, so the GCF is 5.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 15 and 20
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Think it through
Not quite. The answer is
💡 A common factor must divide both numbers with no remainder. 8 ÷ 6 leaves a remainder, and 12 ÷ 6 = 2. 6 does not divide both, so no.
✓ Correct!
Not quite. The answer is
💡 A common factor must divide both numbers with no remainder. 8 ÷ 6 leaves a remainder, and 12 ÷ 6 = 2. 6 does not divide both, so no.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 14 and 16
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 2 is a common factor, but not the greatest one. Factors of 4: 1, 2, 4. Factors of 16: 1, 2, 4, 8, 16. The common factors are 1, 2, 4. The greatest is 4, so the GCF is 4.
✓ Correct!
Not quite. The answer is
💡 2 is a common factor, but not the greatest one. Factors of 4: 1, 2, 4. Factors of 16: 1, 2, 4, 8, 16. The common factors are 1, 2, 4. The greatest is 4, so the GCF is 4.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 3 and 6
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 Factors of 9: 1, 3, 9. Factors of 15: 1, 3, 5, 15. The common factors are 1, 3. The greatest is 3, so the GCF is 3. Divide the top and the bottom by 3: 9 ÷ 3 = 3, and 15 ÷ 3 = 5. So 915 = 35.
✓ Correct!
Not quite. The answer is
💡 Factors of 9: 1, 3, 9. Factors of 15: 1, 3, 5, 15. The common factors are 1, 3. The greatest is 3, so the GCF is 3. Divide the top and the bottom by 3: 9 ÷ 3 = 3, and 15 ÷ 3 = 5. So 915 = 35.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 8 and 14
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Word problems
Not quite. The answer is
💡 The number of bouquets has to divide both 10 and 15, and you want as many as possible, so find the GCF. Factors of 10: 1, 2, 5, 10. Factors of 15: 1, 3, 5, 15. The common factors are 1, 5. The greatest is 5, so the GCF is 5. Each of the 5 bouquets gets 2 roses and 3 tulips.
✓ Correct!
Not quite. The answer is
💡 The number of bouquets has to divide both 10 and 15, and you want as many as possible, so find the GCF. Factors of 10: 1, 2, 5, 10. Factors of 15: 1, 3, 5, 15. The common factors are 1, 5. The greatest is 5, so the GCF is 5. Each of the 5 bouquets gets 2 roses and 3 tulips.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 15 and 20
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Not quite. The answer is
💡 The size of a row has to divide both 4 and 14 evenly, and you want the largest size, so find the GCF. Factors of 4: 1, 2, 4. Factors of 14: 1, 2, 7, 14. The common factors are 1, 2. The greatest is 2, so the GCF is 2. That makes 2 rows of tomato plants and 7 rows of pepper plants.
✓ Correct!
Not quite. The answer is
💡 The size of a row has to divide both 4 and 14 evenly, and you want the largest size, so find the GCF. Factors of 4: 1, 2, 4. Factors of 14: 1, 2, 7, 14. The common factors are 1, 2. The greatest is 2, so the GCF is 2. That makes 2 rows of tomato plants and 7 rows of pepper plants.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 9 and 15
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
Challenge
Not quite. The answer is
💡 Find the largest number that divides all three. Factors of 5: 1, 5. Factors of 10: 1, 2, 5, 10. Factors of 20: 1, 2, 4, 5, 10, 20. The common factors are 1, 5. The greatest is 5, so the GCF is 5.
✓ Correct!
Not quite. The answer is
💡 Find the largest number that divides all three. Factors of 5: 1, 5. Factors of 10: 1, 2, 5, 10. Factors of 20: 1, 2, 4, 5, 10, 20. The common factors are 1, 5. The greatest is 5, so the GCF is 5.
💡 How to solve: GCF of Two Numbers
The GCF is the largest number that divides both numbers with no remainder. List the factors of each number and pick the biggest one they share: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18, so GCF(12, 18) = 6. With bigger numbers, use prime factorizations and multiply the primes they share. When things must be shared into identical groups with nothing left over, the most groups you can make is the GCF.
Try a similar one
GCF of 4 and 14
✓ You've got it! Press Next to keep going. Not yet — the answer is . Read the steps above once more.
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GCF of Two Numbers — Easy Worksheet 1
Answer each question. Every one uses the greatest common factor (GCF).