← 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 585 · 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 + 19 =
  2. 2.78 − 9 =
  3. 3.35 + 9 =
  4. 4.37 + 9 =
  5. 5.37 + 29 =
  6. 6.64 + 9 =
  7. 7.897 − 99 =
  8. 8.340 − 99 =
  9. 9.672 + 99 =
  10. 10.87 − 9 =
  11. 11.50 − 29 =
  12. 12.41 + 19 =
  13. 13.282 − 99 =
  14. 14.53 + 19 =
  15. 15.36 + 19 =
  16. 16.53 + 29 =
  17. 17.32 − 9 =
  18. 18.258 + 99 =
  19. 19.41 − 9 =
  20. 20.15 + 29 =
  21. 21.73 + 29 =
  22. 22.44 − 19 =
  23. 23.53 + 9 =
  24. 24.327 + 99 =
  25. 25.27 − 9 =
  26. 26.109 − 29 =
  27. 27.26 − 19 =
  28. 28.69 + 19 =
  29. 29.83 − 9 =
  30. 30.615 + 99 =
  31. 31.45 + 9 =
  32. 32.61 + 9 =
  33. 33.79 + 19 =
  34. 34.42 + 9 =
  35. 35.773 − 99 =
  36. 36.70 + 29 =
  37. 37.70 + 19 =
  38. 38.66 + 29 =
  39. 39.60 − 29 =
  40. 40.87 − 29 =

Answer key

  1. 97
  2. 69
  3. 44
  4. 46
  5. 66
  6. 73
  7. 798
  8. 241
  9. 771
  10. 78
  11. 21
  12. 60
  13. 183
  14. 72
  15. 55
  16. 82
  17. 23
  18. 357
  19. 32
  20. 44
  21. 102
  22. 25
  23. 62
  24. 426
  25. 18
  26. 80
  27. 7
  28. 88
  29. 74
  30. 714
  31. 54
  32. 70
  33. 98
  34. 51
  35. 674
  36. 99
  37. 89
  38. 95
  39. 31
  40. 58

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