← 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 543 · 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. 1.13 + 9 =
  2. 2.68 + 9 =
  3. 3.46 + 29 =
  4. 4.90 − 19 =
  5. 5.80 + 29 =
  6. 6.27 − 19 =
  7. 7.20 + 9 =
  8. 8.42 + 19 =
  9. 9.642 − 99 =
  10. 10.64 − 9 =
  11. 11.55 + 9 =
  12. 12.31 + 29 =
  13. 13.12 + 19 =
  14. 14.51 + 19 =
  15. 15.237 + 99 =
  16. 16.59 − 9 =
  17. 17.342 − 99 =
  18. 18.133 + 99 =
  19. 19.691 + 99 =
  20. 20.73 − 19 =
  21. 21.70 − 19 =
  22. 22.446 − 99 =
  23. 23.253 + 99 =
  24. 24.88 − 29 =
  25. 25.42 − 19 =
  26. 26.400 − 99 =
  27. 27.73 + 9 =
  28. 28.50 − 29 =
  29. 29.16 + 29 =
  30. 30.512 + 99 =
  31. 31.375 + 99 =
  32. 32.86 − 19 =
  33. 33.21 − 9 =
  34. 34.39 − 29 =
  35. 35.41 − 9 =
  36. 36.52 − 9 =
  37. 37.60 − 9 =
  38. 38.45 + 9 =
  39. 39.429 − 99 =
  40. 40.666 − 99 =

Answer key

  1. 22
  2. 77
  3. 75
  4. 71
  5. 109
  6. 8
  7. 29
  8. 61
  9. 543
  10. 55
  11. 64
  12. 60
  13. 31
  14. 70
  15. 336
  16. 50
  17. 243
  18. 232
  19. 790
  20. 54
  21. 51
  22. 347
  23. 352
  24. 59
  25. 23
  26. 301
  27. 82
  28. 21
  29. 45
  30. 611
  31. 474
  32. 67
  33. 12
  34. 10
  35. 32
  36. 43
  37. 51
  38. 54
  39. 330
  40. 567

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