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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 322 · 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. 1.67 + 9 =
  2. 2.76 + 29 =
  3. 3.19 − 9 =
  4. 4.38 − 19 =
  5. 5.83 − 9 =
  6. 6.67 − 19 =
  7. 7.53 − 9 =
  8. 8.53 + 29 =
  9. 9.64 − 9 =
  10. 10.182 + 99 =
  11. 11.413 − 99 =
  12. 12.33 − 9 =
  13. 13.37 − 19 =
  14. 14.73 − 19 =
  15. 15.62 − 9 =
  16. 16.169 + 99 =
  17. 17.22 + 29 =
  18. 18.98 − 19 =
  19. 19.63 − 29 =
  20. 20.21 + 19 =
  21. 21.94 − 19 =
  22. 22.47 + 19 =
  23. 23.234 + 99 =
  24. 24.574 + 99 =
  25. 25.65 − 19 =
  26. 26.59 − 9 =
  27. 27.54 − 19 =
  28. 28.14 − 9 =
  29. 29.18 + 19 =
  30. 30.24 + 19 =
  31. 31.82 − 19 =
  32. 32.522 − 99 =
  33. 33.202 − 99 =
  34. 34.57 − 29 =
  35. 35.46 − 19 =
  36. 36.36 − 9 =
  37. 37.34 + 9 =
  38. 38.25 + 19 =
  39. 39.87 − 19 =
  40. 40.40 + 9 =

Answer key

  1. 76
  2. 105
  3. 10
  4. 19
  5. 74
  6. 48
  7. 44
  8. 82
  9. 55
  10. 281
  11. 314
  12. 24
  13. 18
  14. 54
  15. 53
  16. 268
  17. 51
  18. 79
  19. 34
  20. 40
  21. 75
  22. 66
  23. 333
  24. 673
  25. 46
  26. 50
  27. 35
  28. 5
  29. 37
  30. 43
  31. 63
  32. 423
  33. 103
  34. 28
  35. 27
  36. 27
  37. 43
  38. 44
  39. 68
  40. 49

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