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Adding 9, 19 and 99 Mental Maths Worksheet

Mental maths lesson 4: Add and take away 9, 19 and 99 · Set 769 · 40 questions
TalentJR

How to do it in your head (Round and adjust): Add 9, 19, 99: add 10, 20, 100, then take 1 away. Take away 9, 19, 99: take away 10, 20, 100, then add 1 back. Ask yourself: did I use too much or too little?

NameDateTime takenScore ___ / 40
  1. 1.83 − 29 =
  2. 2.64 − 9 =
  3. 3.148 + 99 =
  4. 4.62 − 9 =
  5. 5.102 − 29 =
  6. 6.70 + 19 =
  7. 7.33 − 9 =
  8. 8.43 − 19 =
  9. 9.184 − 99 =
  10. 10.38 − 19 =
  11. 11.574 − 99 =
  12. 12.81 − 29 =
  13. 13.19 + 29 =
  14. 14.33 − 29 =
  15. 15.84 − 9 =
  16. 16.257 − 99 =
  17. 17.71 − 9 =
  18. 18.55 + 19 =
  19. 19.100 − 29 =
  20. 20.32 + 9 =
  21. 21.190 + 99 =
  22. 22.79 − 9 =
  23. 23.52 − 19 =
  24. 24.48 − 9 =
  25. 25.50 − 9 =
  26. 26.59 − 29 =
  27. 27.63 − 19 =
  28. 28.12 + 29 =
  29. 29.55 − 9 =
  30. 30.60 + 19 =
  31. 31.280 − 99 =
  32. 32.304 − 99 =
  33. 33.41 − 29 =
  34. 34.602 + 99 =
  35. 35.72 + 9 =
  36. 36.54 − 19 =
  37. 37.78 − 29 =
  38. 38.39 − 19 =
  39. 39.18 + 29 =
  40. 40.15 + 29 =

Answer key

  1. 54
  2. 55
  3. 247
  4. 53
  5. 73
  6. 89
  7. 24
  8. 24
  9. 85
  10. 19
  11. 475
  12. 52
  13. 48
  14. 4
  15. 75
  16. 158
  17. 62
  18. 74
  19. 71
  20. 41
  21. 289
  22. 70
  23. 33
  24. 39
  25. 41
  26. 30
  27. 44
  28. 41
  29. 46
  30. 79
  31. 181
  32. 205
  33. 12
  34. 701
  35. 81
  36. 35
  37. 49
  38. 20
  39. 47
  40. 44

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