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Doubling and Halving Mental Maths Worksheet

Mental maths lesson 9: Doubling and halving · Set 21 · 40 questions
TalentJR

How to do it in your head (Split, then double or halve): To double: split into tens and ones, double both, add. To halve: split into an even number of tens and the rest (156 = 140 + 16). Halve both parts and add.

NameDateTime takenScore ___ / 40
  1. 1.Double 49 =
  2. 2.Double 61 =
  3. 3.Half of 50 =
  4. 4.Double 23 =
  5. 5.Double 38 =
  6. 6.Half of 98 =
  7. 7.Double 33 =
  8. 8.Double 91 =
  9. 9.Double 72 =
  10. 10.Double 29 =
  11. 11.Double 36 =
  12. 12.Half of 108 =
  13. 13.Double 27 =
  14. 14.Double 31 =
  15. 15.Half of 64 =
  16. 16.Half of 62 =
  17. 17.Double 44 =
  18. 18.Double 41 =
  19. 19.Half of 40 =
  20. 20.Half of 128 =
  21. 21.Double 52 =
  22. 22.Double 63 =
  23. 23.Half of 180 =
  24. 24.Half of 190 =
  25. 25.Double 71 =
  26. 26.Double 55 =
  27. 27.Half of 198 =
  28. 28.Half of 150 =
  29. 29.Double 97 =
  30. 30.Double 78 =
  31. 31.Half of 28 =
  32. 32.Half of 66 =
  33. 33.Double 21 =
  34. 34.Half of 120 =
  35. 35.Double 16 =
  36. 36.Half of 172 =
  37. 37.Double 66 =
  38. 38.Half of 92 =
  39. 39.Half of 154 =
  40. 40.Half of 136 =

Answer key

  1. 98
  2. 122
  3. 25
  4. 46
  5. 76
  6. 49
  7. 66
  8. 182
  9. 144
  10. 58
  11. 72
  12. 54
  13. 54
  14. 62
  15. 32
  16. 31
  17. 88
  18. 82
  19. 20
  20. 64
  21. 104
  22. 126
  23. 90
  24. 95
  25. 142
  26. 110
  27. 99
  28. 75
  29. 194
  30. 156
  31. 14
  32. 33
  33. 42
  34. 60
  35. 32
  36. 86
  37. 132
  38. 46
  39. 77
  40. 68

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