← 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 878 · 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. 1.55 + 29 =
  2. 2.78 − 19 =
  3. 3.22 + 19 =
  4. 4.61 − 9 =
  5. 5.460 − 99 =
  6. 6.448 − 99 =
  7. 7.79 − 9 =
  8. 8.66 − 9 =
  9. 9.41 − 29 =
  10. 10.90 − 19 =
  11. 11.59 − 9 =
  12. 12.151 + 99 =
  13. 13.54 + 29 =
  14. 14.35 − 29 =
  15. 15.74 + 9 =
  16. 16.19 + 9 =
  17. 17.77 + 9 =
  18. 18.180 + 99 =
  19. 19.68 + 9 =
  20. 20.63 + 19 =
  21. 21.68 + 19 =
  22. 22.32 − 29 =
  23. 23.23 + 29 =
  24. 24.47 + 19 =
  25. 25.76 + 19 =
  26. 26.14 + 29 =
  27. 27.167 + 99 =
  28. 28.24 − 9 =
  29. 29.622 + 99 =
  30. 30.275 + 99 =
  31. 31.49 − 19 =
  32. 32.43 + 9 =
  33. 33.75 + 19 =
  34. 34.527 + 99 =
  35. 35.625 − 99 =
  36. 36.43 + 19 =
  37. 37.60 − 29 =
  38. 38.78 + 29 =
  39. 39.497 − 99 =
  40. 40.34 − 29 =

Answer key

  1. 84
  2. 59
  3. 41
  4. 52
  5. 361
  6. 349
  7. 70
  8. 57
  9. 12
  10. 71
  11. 50
  12. 250
  13. 83
  14. 6
  15. 83
  16. 28
  17. 86
  18. 279
  19. 77
  20. 82
  21. 87
  22. 3
  23. 52
  24. 66
  25. 95
  26. 43
  27. 266
  28. 15
  29. 721
  30. 374
  31. 30
  32. 52
  33. 94
  34. 626
  35. 526
  36. 62
  37. 31
  38. 107
  39. 398
  40. 5

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