← 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 775 · 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. 1.78 − 29 =
  2. 2.37 − 19 =
  3. 3.73 + 9 =
  4. 4.56 + 9 =
  5. 5.25 − 9 =
  6. 6.18 + 19 =
  7. 7.33 + 19 =
  8. 8.42 + 29 =
  9. 9.57 + 9 =
  10. 10.19 + 9 =
  11. 11.60 + 19 =
  12. 12.637 + 99 =
  13. 13.15 + 29 =
  14. 14.31 + 19 =
  15. 15.338 + 99 =
  16. 16.859 − 99 =
  17. 17.64 − 9 =
  18. 18.24 + 29 =
  19. 19.397 − 99 =
  20. 20.24 − 19 =
  21. 21.715 + 99 =
  22. 22.430 + 99 =
  23. 23.509 + 99 =
  24. 24.74 − 19 =
  25. 25.60 − 9 =
  26. 26.44 − 9 =
  27. 27.70 + 9 =
  28. 28.13 + 29 =
  29. 29.13 + 19 =
  30. 30.61 + 29 =
  31. 31.145 + 99 =
  32. 32.28 + 19 =
  33. 33.55 + 29 =
  34. 34.89 − 19 =
  35. 35.79 + 19 =
  36. 36.746 + 99 =
  37. 37.52 − 19 =
  38. 38.53 + 9 =
  39. 39.54 + 29 =
  40. 40.56 + 29 =

Answer key

  1. 49
  2. 18
  3. 82
  4. 65
  5. 16
  6. 37
  7. 52
  8. 71
  9. 66
  10. 28
  11. 79
  12. 736
  13. 44
  14. 50
  15. 437
  16. 760
  17. 55
  18. 53
  19. 298
  20. 5
  21. 814
  22. 529
  23. 608
  24. 55
  25. 51
  26. 35
  27. 79
  28. 42
  29. 32
  30. 90
  31. 244
  32. 47
  33. 84
  34. 70
  35. 98
  36. 845
  37. 33
  38. 62
  39. 83
  40. 85

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