← 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 68 · 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. 1.25 + 19 =
  2. 2.12 + 19 =
  3. 3.77 − 9 =
  4. 4.498 + 99 =
  5. 5.192 + 99 =
  6. 6.24 − 9 =
  7. 7.256 + 99 =
  8. 8.17 + 19 =
  9. 9.86 − 9 =
  10. 10.95 − 19 =
  11. 11.69 − 19 =
  12. 12.30 − 19 =
  13. 13.46 + 19 =
  14. 14.31 + 9 =
  15. 15.218 + 99 =
  16. 16.66 − 19 =
  17. 17.63 + 9 =
  18. 18.30 + 19 =
  19. 19.378 + 99 =
  20. 20.184 − 99 =
  21. 21.25 + 29 =
  22. 22.581 − 99 =
  23. 23.12 + 9 =
  24. 24.47 + 9 =
  25. 25.16 + 9 =
  26. 26.717 − 99 =
  27. 27.73 + 19 =
  28. 28.78 + 9 =
  29. 29.249 + 99 =
  30. 30.374 − 99 =
  31. 31.19 + 19 =
  32. 32.46 − 29 =
  33. 33.688 + 99 =
  34. 34.52 − 19 =
  35. 35.99 − 19 =
  36. 36.24 + 19 =
  37. 37.791 − 99 =
  38. 38.51 + 29 =
  39. 39.57 − 9 =
  40. 40.46 + 9 =

Answer key

  1. 44
  2. 31
  3. 68
  4. 597
  5. 291
  6. 15
  7. 355
  8. 36
  9. 77
  10. 76
  11. 50
  12. 11
  13. 65
  14. 40
  15. 317
  16. 47
  17. 72
  18. 49
  19. 477
  20. 85
  21. 54
  22. 482
  23. 21
  24. 56
  25. 25
  26. 618
  27. 92
  28. 87
  29. 348
  30. 275
  31. 38
  32. 17
  33. 787
  34. 33
  35. 80
  36. 43
  37. 692
  38. 80
  39. 48
  40. 55

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