← 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 233 · 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. 1.37 + 19 =
  2. 2.236 − 99 =
  3. 3.23 + 19 =
  4. 4.550 + 99 =
  5. 5.79 + 29 =
  6. 6.90 − 29 =
  7. 7.16 + 9 =
  8. 8.58 + 29 =
  9. 9.79 + 19 =
  10. 10.73 + 19 =
  11. 11.150 + 99 =
  12. 12.61 + 29 =
  13. 13.53 + 29 =
  14. 14.823 − 99 =
  15. 15.80 − 9 =
  16. 16.93 − 29 =
  17. 17.618 + 99 =
  18. 18.309 − 99 =
  19. 19.755 + 99 =
  20. 20.67 − 29 =
  21. 21.80 + 9 =
  22. 22.99 − 29 =
  23. 23.74 − 9 =
  24. 24.59 + 19 =
  25. 25.36 + 19 =
  26. 26.42 − 19 =
  27. 27.15 − 9 =
  28. 28.77 − 29 =
  29. 29.25 − 19 =
  30. 30.60 + 29 =
  31. 31.62 + 29 =
  32. 32.24 − 19 =
  33. 33.23 − 9 =
  34. 34.572 + 99 =
  35. 35.36 − 19 =
  36. 36.59 + 29 =
  37. 37.648 + 99 =
  38. 38.681 + 99 =
  39. 39.379 + 99 =
  40. 40.96 − 19 =

Answer key

  1. 56
  2. 137
  3. 42
  4. 649
  5. 108
  6. 61
  7. 25
  8. 87
  9. 98
  10. 92
  11. 249
  12. 90
  13. 82
  14. 724
  15. 71
  16. 64
  17. 717
  18. 210
  19. 854
  20. 38
  21. 89
  22. 70
  23. 65
  24. 78
  25. 55
  26. 23
  27. 6
  28. 48
  29. 6
  30. 89
  31. 91
  32. 5
  33. 14
  34. 671
  35. 17
  36. 88
  37. 747
  38. 780
  39. 478
  40. 77

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