Highest common factor and lowest common multiple
Name: _____________________ Date: __________
Show your thinking with numbers, words, or a drawing.
1. The factors of 35 are 1, 5, 7, 35. The factors of 10 are 1, 2, 5, 10. What is the highest common factor of 35 and 10?
2. The factors of 21 are 1, 3, 7, 21. The factors of 6 are 1, 2, 3, 6. What is the highest common factor of 21 and 6?
3. The factors of 28 are 1, 2, 4, 7, 14, 28. The factors of 8 are 1, 2, 4, 8. What is the highest common factor of 28 and 8?
4. The factors of 9 are 1, 3, 9. The factors of 15 are 1, 3, 5, 15. What is the highest common factor of 9 and 15?
5. The factors of 8 are 1, 2, 4, 8. The factors of 14 are 1, 2, 7, 14. What is the highest common factor of 8 and 14?
Answer key ยท Highest common factor and lowest common multiple
1. 5
Factors of 35: 1, 5, 7, 35. Factors of 10: 1, 2, 5, 10.
The common factors are 1, 5.
The highest common factor is 5.
2. 3
Factors of 21: 1, 3, 7, 21. Factors of 6: 1, 2, 3, 6.
The common factors are 1, 3.
The highest common factor is 3.
3. 4
Factors of 28: 1, 2, 4, 7, 14, 28. Factors of 8: 1, 2, 4, 8.
The common factors are 1, 2, 4.
The highest common factor is 4.
4. 3
Factors of 9: 1, 3, 9. Factors of 15: 1, 3, 5, 15.
The common factors are 1, 3.
The highest common factor is 3.
5. 2
Factors of 8: 1, 2, 4, 8. Factors of 14: 1, 2, 7, 14.
The common factors are 1, 2.
The highest common factor is 2.
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