← 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 217 · 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. 1.505 − 99 =
  2. 2.484 + 99 =
  3. 3.50 + 19 =
  4. 4.32 + 9 =
  5. 5.61 + 9 =
  6. 6.695 + 99 =
  7. 7.69 + 19 =
  8. 8.48 + 9 =
  9. 9.67 + 19 =
  10. 10.73 − 9 =
  11. 11.35 + 29 =
  12. 12.367 + 99 =
  13. 13.88 − 29 =
  14. 14.65 + 9 =
  15. 15.30 + 9 =
  16. 16.72 − 19 =
  17. 17.15 + 9 =
  18. 18.401 − 99 =
  19. 19.273 + 99 =
  20. 20.42 + 19 =
  21. 21.31 − 9 =
  22. 22.493 + 99 =
  23. 23.21 + 29 =
  24. 24.25 − 19 =
  25. 25.56 + 9 =
  26. 26.646 − 99 =
  27. 27.22 + 19 =
  28. 28.93 − 19 =
  29. 29.53 − 29 =
  30. 30.60 − 9 =
  31. 31.49 − 9 =
  32. 32.60 + 19 =
  33. 33.20 + 29 =
  34. 34.14 − 9 =
  35. 35.757 + 99 =
  36. 36.750 + 99 =
  37. 37.48 − 9 =
  38. 38.64 + 19 =
  39. 39.79 − 29 =
  40. 40.101 − 29 =

Answer key

  1. 406
  2. 583
  3. 69
  4. 41
  5. 70
  6. 794
  7. 88
  8. 57
  9. 86
  10. 64
  11. 64
  12. 466
  13. 59
  14. 74
  15. 39
  16. 53
  17. 24
  18. 302
  19. 372
  20. 61
  21. 22
  22. 592
  23. 50
  24. 6
  25. 65
  26. 547
  27. 41
  28. 74
  29. 24
  30. 51
  31. 40
  32. 79
  33. 49
  34. 5
  35. 856
  36. 849
  37. 39
  38. 83
  39. 50
  40. 72

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