← 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 680 · 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. 1.186 + 99 =
  2. 2.55 + 9 =
  3. 3.37 − 9 =
  4. 4.433 − 99 =
  5. 5.73 + 9 =
  6. 6.731 + 99 =
  7. 7.50 − 9 =
  8. 8.31 + 19 =
  9. 9.47 + 19 =
  10. 10.685 − 99 =
  11. 11.577 − 99 =
  12. 12.27 − 9 =
  13. 13.422 + 99 =
  14. 14.17 + 19 =
  15. 15.13 + 9 =
  16. 16.79 − 29 =
  17. 17.50 + 19 =
  18. 18.25 − 19 =
  19. 19.29 + 29 =
  20. 20.27 − 19 =
  21. 21.176 + 99 =
  22. 22.322 − 99 =
  23. 23.71 + 19 =
  24. 24.280 + 99 =
  25. 25.339 − 99 =
  26. 26.40 + 29 =
  27. 27.39 − 9 =
  28. 28.44 − 19 =
  29. 29.19 + 9 =
  30. 30.66 + 29 =
  31. 31.69 + 19 =
  32. 32.73 − 19 =
  33. 33.24 + 29 =
  34. 34.31 + 9 =
  35. 35.39 + 19 =
  36. 36.106 − 29 =
  37. 37.41 − 19 =
  38. 38.484 + 99 =
  39. 39.78 − 29 =
  40. 40.64 − 9 =

Answer key

  1. 285
  2. 64
  3. 28
  4. 334
  5. 82
  6. 830
  7. 41
  8. 50
  9. 66
  10. 586
  11. 478
  12. 18
  13. 521
  14. 36
  15. 22
  16. 50
  17. 69
  18. 6
  19. 58
  20. 8
  21. 275
  22. 223
  23. 90
  24. 379
  25. 240
  26. 69
  27. 30
  28. 25
  29. 28
  30. 95
  31. 88
  32. 54
  33. 53
  34. 40
  35. 58
  36. 77
  37. 22
  38. 583
  39. 49
  40. 55

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