← Add and take away 9, 19 and 99 lesson New set →

Adding 9, 19 and 99 Mental Maths Worksheet

Mental maths lesson 4: Add and take away 9, 19 and 99 · Set 628 · 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 − 9 =
  2. 2.81 − 9 =
  3. 3.620 + 99 =
  4. 4.394 − 99 =
  5. 5.34 + 29 =
  6. 6.83 − 19 =
  7. 7.69 + 9 =
  8. 8.66 + 9 =
  9. 9.32 − 9 =
  10. 10.38 − 19 =
  11. 11.22 − 19 =
  12. 12.76 + 9 =
  13. 13.737 + 99 =
  14. 14.79 + 19 =
  15. 15.75 − 9 =
  16. 16.95 − 19 =
  17. 17.68 + 19 =
  18. 18.39 − 19 =
  19. 19.18 + 9 =
  20. 20.70 − 9 =
  21. 21.55 + 9 =
  22. 22.56 + 9 =
  23. 23.476 + 99 =
  24. 24.36 − 19 =
  25. 25.18 − 9 =
  26. 26.19 + 9 =
  27. 27.235 + 99 =
  28. 28.19 − 9 =
  29. 29.23 + 29 =
  30. 30.72 − 9 =
  31. 31.39 + 19 =
  32. 32.370 − 99 =
  33. 33.103 − 29 =
  34. 34.42 + 19 =
  35. 35.49 − 9 =
  36. 36.61 − 29 =
  37. 37.327 + 99 =
  38. 38.483 − 99 =
  39. 39.68 + 29 =
  40. 40.809 − 99 =

Answer key

  1. 74
  2. 72
  3. 719
  4. 295
  5. 63
  6. 64
  7. 78
  8. 75
  9. 23
  10. 19
  11. 3
  12. 85
  13. 836
  14. 98
  15. 66
  16. 76
  17. 87
  18. 20
  19. 27
  20. 61
  21. 64
  22. 65
  23. 575
  24. 17
  25. 9
  26. 28
  27. 334
  28. 10
  29. 52
  30. 63
  31. 58
  32. 271
  33. 74
  34. 61
  35. 40
  36. 32
  37. 426
  38. 384
  39. 97
  40. 710

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths