← 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 109 · 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. 1.42 − 19 =
  2. 2.73 + 19 =
  3. 3.792 + 99 =
  4. 4.89 − 29 =
  5. 5.13 + 19 =
  6. 6.79 + 29 =
  7. 7.73 − 9 =
  8. 8.850 − 99 =
  9. 9.52 + 9 =
  10. 10.637 − 99 =
  11. 11.32 + 19 =
  12. 12.39 − 29 =
  13. 13.16 + 29 =
  14. 14.275 + 99 =
  15. 15.772 − 99 =
  16. 16.23 + 19 =
  17. 17.43 + 29 =
  18. 18.60 + 29 =
  19. 19.39 + 9 =
  20. 20.83 − 9 =
  21. 21.58 − 19 =
  22. 22.224 + 99 =
  23. 23.98 − 29 =
  24. 24.513 + 99 =
  25. 25.80 − 29 =
  26. 26.13 + 9 =
  27. 27.21 + 9 =
  28. 28.65 + 29 =
  29. 29.52 + 29 =
  30. 30.63 + 19 =
  31. 31.767 − 99 =
  32. 32.15 − 9 =
  33. 33.472 − 99 =
  34. 34.37 − 29 =
  35. 35.17 + 9 =
  36. 36.26 − 9 =
  37. 37.76 − 29 =
  38. 38.18 − 9 =
  39. 39.244 − 99 =
  40. 40.708 − 99 =

Answer key

  1. 23
  2. 92
  3. 891
  4. 60
  5. 32
  6. 108
  7. 64
  8. 751
  9. 61
  10. 538
  11. 51
  12. 10
  13. 45
  14. 374
  15. 673
  16. 42
  17. 72
  18. 89
  19. 48
  20. 74
  21. 39
  22. 323
  23. 69
  24. 612
  25. 51
  26. 22
  27. 30
  28. 94
  29. 81
  30. 82
  31. 668
  32. 6
  33. 373
  34. 8
  35. 26
  36. 17
  37. 47
  38. 9
  39. 145
  40. 609

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