← 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 465 · 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. 1.70 + 19 =
  2. 2.16 + 29 =
  3. 3.14 − 9 =
  4. 4.67 + 9 =
  5. 5.171 − 99 =
  6. 6.107 − 29 =
  7. 7.37 − 29 =
  8. 8.84 − 9 =
  9. 9.50 + 19 =
  10. 10.88 − 9 =
  11. 11.64 + 9 =
  12. 12.69 − 19 =
  13. 13.86 − 19 =
  14. 14.65 + 29 =
  15. 15.73 + 9 =
  16. 16.802 − 99 =
  17. 17.52 + 19 =
  18. 18.28 − 9 =
  19. 19.214 − 99 =
  20. 20.77 − 19 =
  21. 21.858 − 99 =
  22. 22.78 − 29 =
  23. 23.97 − 29 =
  24. 24.839 − 99 =
  25. 25.40 + 19 =
  26. 26.12 + 19 =
  27. 27.534 + 99 =
  28. 28.41 + 19 =
  29. 29.13 + 29 =
  30. 30.38 − 29 =
  31. 31.64 − 19 =
  32. 32.85 − 9 =
  33. 33.71 + 19 =
  34. 34.35 − 19 =
  35. 35.467 − 99 =
  36. 36.36 − 19 =
  37. 37.814 − 99 =
  38. 38.69 + 29 =
  39. 39.85 − 19 =
  40. 40.15 + 9 =

Answer key

  1. 89
  2. 45
  3. 5
  4. 76
  5. 72
  6. 78
  7. 8
  8. 75
  9. 69
  10. 79
  11. 73
  12. 50
  13. 67
  14. 94
  15. 82
  16. 703
  17. 71
  18. 19
  19. 115
  20. 58
  21. 759
  22. 49
  23. 68
  24. 740
  25. 59
  26. 31
  27. 633
  28. 60
  29. 42
  30. 9
  31. 45
  32. 76
  33. 90
  34. 16
  35. 368
  36. 17
  37. 715
  38. 98
  39. 66
  40. 24

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