← 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 782 · 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. 1.41 − 29 =
  2. 2.35 + 19 =
  3. 3.196 − 99 =
  4. 4.50 − 29 =
  5. 5.19 + 9 =
  6. 6.79 + 9 =
  7. 7.447 − 99 =
  8. 8.777 − 99 =
  9. 9.83 − 29 =
  10. 10.38 + 19 =
  11. 11.748 + 99 =
  12. 12.20 + 29 =
  13. 13.645 − 99 =
  14. 14.109 − 29 =
  15. 15.29 + 9 =
  16. 16.156 − 99 =
  17. 17.87 − 29 =
  18. 18.75 + 9 =
  19. 19.83 − 19 =
  20. 20.74 − 9 =
  21. 21.38 + 9 =
  22. 22.14 + 9 =
  23. 23.75 + 29 =
  24. 24.537 + 99 =
  25. 25.89 − 9 =
  26. 26.34 + 9 =
  27. 27.38 − 29 =
  28. 28.52 − 29 =
  29. 29.52 − 9 =
  30. 30.50 + 9 =
  31. 31.467 − 99 =
  32. 32.25 + 9 =
  33. 33.207 + 99 =
  34. 34.213 + 99 =
  35. 35.71 + 9 =
  36. 36.387 + 99 =
  37. 37.56 + 19 =
  38. 38.35 + 29 =
  39. 39.516 − 99 =
  40. 40.75 + 19 =

Answer key

  1. 12
  2. 54
  3. 97
  4. 21
  5. 28
  6. 88
  7. 348
  8. 678
  9. 54
  10. 57
  11. 847
  12. 49
  13. 546
  14. 80
  15. 38
  16. 57
  17. 58
  18. 84
  19. 64
  20. 65
  21. 47
  22. 23
  23. 104
  24. 636
  25. 80
  26. 43
  27. 9
  28. 23
  29. 43
  30. 59
  31. 368
  32. 34
  33. 306
  34. 312
  35. 80
  36. 486
  37. 75
  38. 64
  39. 417
  40. 94

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