← 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 925 · 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. 1.53 + 19 =
  2. 2.898 − 99 =
  3. 3.16 + 9 =
  4. 4.73 − 9 =
  5. 5.203 − 99 =
  6. 6.75 + 9 =
  7. 7.46 + 9 =
  8. 8.17 + 19 =
  9. 9.66 − 19 =
  10. 10.43 + 9 =
  11. 11.851 − 99 =
  12. 12.209 + 99 =
  13. 13.32 − 29 =
  14. 14.67 + 29 =
  15. 15.248 − 99 =
  16. 16.737 + 99 =
  17. 17.444 − 99 =
  18. 18.344 + 99 =
  19. 19.38 + 9 =
  20. 20.564 + 99 =
  21. 21.202 + 99 =
  22. 22.27 − 9 =
  23. 23.91 − 29 =
  24. 24.72 − 19 =
  25. 25.703 − 99 =
  26. 26.13 + 9 =
  27. 27.21 − 9 =
  28. 28.667 + 99 =
  29. 29.709 − 99 =
  30. 30.18 + 19 =
  31. 31.39 − 19 =
  32. 32.367 + 99 =
  33. 33.43 − 29 =
  34. 34.86 − 9 =
  35. 35.38 − 29 =
  36. 36.24 − 9 =
  37. 37.60 − 19 =
  38. 38.40 − 29 =
  39. 39.66 + 9 =
  40. 40.71 + 29 =

Answer key

  1. 72
  2. 799
  3. 25
  4. 64
  5. 104
  6. 84
  7. 55
  8. 36
  9. 47
  10. 52
  11. 752
  12. 308
  13. 3
  14. 96
  15. 149
  16. 836
  17. 345
  18. 443
  19. 47
  20. 663
  21. 301
  22. 18
  23. 62
  24. 53
  25. 604
  26. 22
  27. 12
  28. 766
  29. 610
  30. 37
  31. 20
  32. 466
  33. 14
  34. 77
  35. 9
  36. 15
  37. 41
  38. 11
  39. 75
  40. 100

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