← 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 361 · 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. 1.63 + 9 =
  2. 2.12 + 19 =
  3. 3.341 − 99 =
  4. 4.619 + 99 =
  5. 5.77 − 9 =
  6. 6.117 + 99 =
  7. 7.47 + 29 =
  8. 8.52 + 29 =
  9. 9.590 − 99 =
  10. 10.18 + 9 =
  11. 11.53 − 29 =
  12. 12.71 + 29 =
  13. 13.47 − 19 =
  14. 14.651 − 99 =
  15. 15.306 + 99 =
  16. 16.51 − 19 =
  17. 17.34 − 9 =
  18. 18.87 − 9 =
  19. 19.86 − 29 =
  20. 20.71 − 29 =
  21. 21.27 − 19 =
  22. 22.16 + 9 =
  23. 23.171 − 99 =
  24. 24.49 − 9 =
  25. 25.81 − 29 =
  26. 26.38 + 9 =
  27. 27.53 + 9 =
  28. 28.33 − 19 =
  29. 29.72 + 9 =
  30. 30.73 − 9 =
  31. 31.48 + 29 =
  32. 32.40 + 29 =
  33. 33.105 + 99 =
  34. 34.25 + 19 =
  35. 35.61 − 9 =
  36. 36.322 − 99 =
  37. 37.94 − 29 =
  38. 38.15 − 9 =
  39. 39.161 + 99 =
  40. 40.35 − 19 =

Answer key

  1. 72
  2. 31
  3. 242
  4. 718
  5. 68
  6. 216
  7. 76
  8. 81
  9. 491
  10. 27
  11. 24
  12. 100
  13. 28
  14. 552
  15. 405
  16. 32
  17. 25
  18. 78
  19. 57
  20. 42
  21. 8
  22. 25
  23. 72
  24. 40
  25. 52
  26. 47
  27. 62
  28. 14
  29. 81
  30. 64
  31. 77
  32. 69
  33. 204
  34. 44
  35. 52
  36. 223
  37. 65
  38. 6
  39. 260
  40. 16

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