← 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 948 · 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. 1.49 − 29 =
  2. 2.899 − 99 =
  3. 3.80 + 29 =
  4. 4.27 + 29 =
  5. 5.683 + 99 =
  6. 6.36 + 29 =
  7. 7.170 + 99 =
  8. 8.68 + 9 =
  9. 9.69 − 9 =
  10. 10.51 − 29 =
  11. 11.83 − 19 =
  12. 12.97 − 29 =
  13. 13.673 + 99 =
  14. 14.76 − 19 =
  15. 15.31 − 9 =
  16. 16.26 − 19 =
  17. 17.625 + 99 =
  18. 18.23 + 29 =
  19. 19.17 + 9 =
  20. 20.32 − 19 =
  21. 21.78 + 29 =
  22. 22.78 + 19 =
  23. 23.49 − 19 =
  24. 24.99 − 29 =
  25. 25.91 − 29 =
  26. 26.155 − 99 =
  27. 27.151 + 99 =
  28. 28.53 + 19 =
  29. 29.38 + 9 =
  30. 30.677 + 99 =
  31. 31.23 − 9 =
  32. 32.50 + 29 =
  33. 33.26 + 29 =
  34. 34.327 + 99 =
  35. 35.38 − 19 =
  36. 36.35 − 19 =
  37. 37.42 − 29 =
  38. 38.59 − 19 =
  39. 39.47 + 9 =
  40. 40.38 − 9 =

Answer key

  1. 20
  2. 800
  3. 109
  4. 56
  5. 782
  6. 65
  7. 269
  8. 77
  9. 60
  10. 22
  11. 64
  12. 68
  13. 772
  14. 57
  15. 22
  16. 7
  17. 724
  18. 52
  19. 26
  20. 13
  21. 107
  22. 97
  23. 30
  24. 70
  25. 62
  26. 56
  27. 250
  28. 72
  29. 47
  30. 776
  31. 14
  32. 79
  33. 55
  34. 426
  35. 19
  36. 16
  37. 13
  38. 40
  39. 56
  40. 29

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