← 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 245 · 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. 1.34 + 29 =
  2. 2.34 + 9 =
  3. 3.81 − 19 =
  4. 4.14 + 29 =
  5. 5.51 + 19 =
  6. 6.46 + 19 =
  7. 7.17 + 29 =
  8. 8.84 − 19 =
  9. 9.252 + 99 =
  10. 10.39 + 9 =
  11. 11.86 − 19 =
  12. 12.255 − 99 =
  13. 13.69 + 9 =
  14. 14.93 − 19 =
  15. 15.54 + 29 =
  16. 16.34 + 19 =
  17. 17.16 + 9 =
  18. 18.37 − 29 =
  19. 19.77 + 19 =
  20. 20.22 + 9 =
  21. 21.733 − 99 =
  22. 22.83 − 29 =
  23. 23.52 − 9 =
  24. 24.49 − 19 =
  25. 25.15 − 9 =
  26. 26.91 − 29 =
  27. 27.80 + 19 =
  28. 28.20 + 19 =
  29. 29.53 + 29 =
  30. 30.18 − 9 =
  31. 31.501 − 99 =
  32. 32.499 − 99 =
  33. 33.369 − 99 =
  34. 34.206 − 99 =
  35. 35.31 + 9 =
  36. 36.76 − 19 =
  37. 37.40 − 29 =
  38. 38.22 + 19 =
  39. 39.42 − 29 =
  40. 40.44 − 9 =

Answer key

  1. 63
  2. 43
  3. 62
  4. 43
  5. 70
  6. 65
  7. 46
  8. 65
  9. 351
  10. 48
  11. 67
  12. 156
  13. 78
  14. 74
  15. 83
  16. 53
  17. 25
  18. 8
  19. 96
  20. 31
  21. 634
  22. 54
  23. 43
  24. 30
  25. 6
  26. 62
  27. 99
  28. 39
  29. 82
  30. 9
  31. 402
  32. 400
  33. 270
  34. 107
  35. 40
  36. 57
  37. 11
  38. 41
  39. 13
  40. 35

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