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Rewrite a sum of two numbers to 100 using the GCF

Year 7 maths · Fieldbook Learning

Name ______________________ Date __________

Pull out the greatest common factor, then write the two leftover numbers in brackets. Use spaces: GCF(first + second).

  1. Rewrite 5 + 15 as the GCF times a sum, like 4(9 + 2).
  2. Use the GCF to rewrite 16 + 4 as a product: GCF(sum of two numbers with no common factor).
  3. Rewrite 10 + 6 as the GCF times a sum, like 4(9 + 2).
  4. Rewrite 12 + 6 as the GCF times a sum, like 4(9 + 2).
  5. Use the GCF to rewrite 39 + 26 as a product: GCF(sum of two numbers with no common factor).
  6. Rewrite 28 + 7 as the GCF times a sum, like 4(9 + 2).
  7. Rewrite 24 + 32 as the GCF times a sum, like 4(9 + 2).
  8. Rewrite 36 + 9 as the GCF times a sum, like 4(9 + 2).
  9. Use the GCF to rewrite 60 + 57 as a product: GCF(sum of two numbers with no common factor).
  10. Use the GCF to rewrite 45 + 25 as a product: GCF(sum of two numbers with no common factor).
  11. Use the GCF to rewrite 45 + 54 as a product: GCF(sum of two numbers with no common factor).
  12. Rewrite 30 + 10 as the GCF times a sum, like 4(9 + 2).
  13. Rewrite 77 + 55 as the GCF times a sum, like 4(9 + 2).
  14. Rewrite 52 + 78 as the GCF times a sum, like 4(9 + 2).
  15. Rewrite 42 + 14 as the GCF times a sum, like 4(9 + 2).
  16. Rewrite 17 + 34 as the GCF times a sum, like 4(9 + 2).
  17. Use the GCF to rewrite 19 + 38 as a product: GCF(sum of two numbers with no common factor).
  18. Use the GCF to rewrite 20 + 60 as a product: GCF(sum of two numbers with no common factor).
  19. Rewrite 84 + 63 as the GCF times a sum, like 4(9 + 2).
  20. Use the GCF to rewrite 60 + 75 as a product: GCF(sum of two numbers with no common factor).
More free practice: fieldbooklearning.com/uk/practice/year-7/rewrite-a-sum-of-two-numbers-to-100-using-the-gcf/

Answer key: Rewrite a sum of two numbers to 100 using the GCF

  1. 5(1 + 3)
  2. 4(4 + 1)
  3. 2(5 + 3)
  4. 6(2 + 1)
  5. 13(3 + 2)
  6. 7(4 + 1)
  7. 8(3 + 4)
  8. 9(4 + 1)
  9. 3(20 + 19)
  10. 5(9 + 5)
  11. 9(5 + 6)
  12. 10(3 + 1)
  13. 11(7 + 5)
  14. 26(2 + 3)
  15. 14(3 + 1)
  16. 17(1 + 2)
  17. 19(1 + 2)
  18. 20(1 + 3)
  19. 21(4 + 3)
  20. 15(4 + 5)