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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 176 · 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. 1.72 + 29 =
  2. 2.25 + 29 =
  3. 3.41 − 9 =
  4. 4.47 + 19 =
  5. 5.38 + 9 =
  6. 6.56 − 29 =
  7. 7.38 − 19 =
  8. 8.80 − 19 =
  9. 9.23 + 9 =
  10. 10.14 − 9 =
  11. 11.70 − 19 =
  12. 12.66 + 19 =
  13. 13.72 − 29 =
  14. 14.144 + 99 =
  15. 15.41 − 19 =
  16. 16.32 + 9 =
  17. 17.59 − 19 =
  18. 18.19 + 9 =
  19. 19.85 − 9 =
  20. 20.323 + 99 =
  21. 21.74 + 29 =
  22. 22.64 + 19 =
  23. 23.17 + 19 =
  24. 24.34 + 9 =
  25. 25.78 − 9 =
  26. 26.27 − 9 =
  27. 27.297 − 99 =
  28. 28.18 + 29 =
  29. 29.82 − 29 =
  30. 30.17 + 29 =
  31. 31.54 + 29 =
  32. 32.158 + 99 =
  33. 33.28 + 29 =
  34. 34.104 − 29 =
  35. 35.287 − 99 =
  36. 36.82 − 19 =
  37. 37.66 − 29 =
  38. 38.70 + 9 =
  39. 39.43 + 29 =
  40. 40.29 + 9 =

Answer key

  1. 101
  2. 54
  3. 32
  4. 66
  5. 47
  6. 27
  7. 19
  8. 61
  9. 32
  10. 5
  11. 51
  12. 85
  13. 43
  14. 243
  15. 22
  16. 41
  17. 40
  18. 28
  19. 76
  20. 422
  21. 103
  22. 83
  23. 36
  24. 43
  25. 69
  26. 18
  27. 198
  28. 47
  29. 53
  30. 46
  31. 83
  32. 257
  33. 57
  34. 75
  35. 188
  36. 63
  37. 37
  38. 79
  39. 72
  40. 38

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