← 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 483 · 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. 1.103 − 29 =
  2. 2.70 + 9 =
  3. 3.30 + 29 =
  4. 4.404 − 99 =
  5. 5.32 + 9 =
  6. 6.58 + 19 =
  7. 7.843 − 99 =
  8. 8.24 + 9 =
  9. 9.90 − 29 =
  10. 10.49 + 29 =
  11. 11.60 + 9 =
  12. 12.58 − 29 =
  13. 13.58 − 9 =
  14. 14.777 − 99 =
  15. 15.79 + 29 =
  16. 16.46 + 9 =
  17. 17.53 − 29 =
  18. 18.93 − 19 =
  19. 19.55 − 19 =
  20. 20.44 − 9 =
  21. 21.34 + 29 =
  22. 22.29 + 9 =
  23. 23.74 − 29 =
  24. 24.58 + 9 =
  25. 25.321 − 99 =
  26. 26.20 + 19 =
  27. 27.12 + 29 =
  28. 28.71 + 29 =
  29. 29.63 + 9 =
  30. 30.221 + 99 =
  31. 31.38 − 29 =
  32. 32.34 + 19 =
  33. 33.41 + 29 =
  34. 34.435 − 99 =
  35. 35.80 − 19 =
  36. 36.67 + 9 =
  37. 37.35 − 19 =
  38. 38.36 + 9 =
  39. 39.78 + 9 =
  40. 40.483 + 99 =

Answer key

  1. 74
  2. 79
  3. 59
  4. 305
  5. 41
  6. 77
  7. 744
  8. 33
  9. 61
  10. 78
  11. 69
  12. 29
  13. 49
  14. 678
  15. 108
  16. 55
  17. 24
  18. 74
  19. 36
  20. 35
  21. 63
  22. 38
  23. 45
  24. 67
  25. 222
  26. 39
  27. 41
  28. 100
  29. 72
  30. 320
  31. 9
  32. 53
  33. 70
  34. 336
  35. 61
  36. 76
  37. 16
  38. 45
  39. 87
  40. 582

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