← 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 92 · 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. 1.31 − 19 =
  2. 2.45 + 9 =
  3. 3.67 + 29 =
  4. 4.32 + 9 =
  5. 5.58 + 19 =
  6. 6.74 − 9 =
  7. 7.740 + 99 =
  8. 8.64 + 19 =
  9. 9.430 − 99 =
  10. 10.799 − 99 =
  11. 11.19 − 9 =
  12. 12.36 + 9 =
  13. 13.15 − 9 =
  14. 14.70 + 9 =
  15. 15.87 − 19 =
  16. 16.60 + 9 =
  17. 17.339 + 99 =
  18. 18.78 − 19 =
  19. 19.79 + 19 =
  20. 20.78 + 9 =
  21. 21.789 + 99 =
  22. 22.43 + 19 =
  23. 23.37 − 9 =
  24. 24.393 − 99 =
  25. 25.347 − 99 =
  26. 26.517 − 99 =
  27. 27.34 − 19 =
  28. 28.37 + 29 =
  29. 29.44 − 19 =
  30. 30.553 − 99 =
  31. 31.77 − 9 =
  32. 32.86 − 9 =
  33. 33.56 − 19 =
  34. 34.73 + 19 =
  35. 35.55 + 19 =
  36. 36.48 + 19 =
  37. 37.15 + 29 =
  38. 38.73 − 19 =
  39. 39.491 + 99 =
  40. 40.618 + 99 =

Answer key

  1. 12
  2. 54
  3. 96
  4. 41
  5. 77
  6. 65
  7. 839
  8. 83
  9. 331
  10. 700
  11. 10
  12. 45
  13. 6
  14. 79
  15. 68
  16. 69
  17. 438
  18. 59
  19. 98
  20. 87
  21. 888
  22. 62
  23. 28
  24. 294
  25. 248
  26. 418
  27. 15
  28. 66
  29. 25
  30. 454
  31. 68
  32. 77
  33. 37
  34. 92
  35. 74
  36. 67
  37. 44
  38. 54
  39. 590
  40. 717

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