← 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 619 · 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. 1.56 + 29 =
  2. 2.100 − 29 =
  3. 3.690 − 99 =
  4. 4.80 + 9 =
  5. 5.108 − 29 =
  6. 6.787 − 99 =
  7. 7.35 − 19 =
  8. 8.44 − 19 =
  9. 9.26 + 9 =
  10. 10.29 + 9 =
  11. 11.14 + 19 =
  12. 12.265 − 99 =
  13. 13.823 − 99 =
  14. 14.54 − 29 =
  15. 15.48 − 9 =
  16. 16.72 + 19 =
  17. 17.746 + 99 =
  18. 18.42 + 19 =
  19. 19.51 + 19 =
  20. 20.634 + 99 =
  21. 21.22 − 9 =
  22. 22.34 − 29 =
  23. 23.30 + 9 =
  24. 24.92 − 29 =
  25. 25.489 − 99 =
  26. 26.25 + 9 =
  27. 27.14 + 29 =
  28. 28.31 + 9 =
  29. 29.161 + 99 =
  30. 30.66 − 19 =
  31. 31.473 − 99 =
  32. 32.41 − 19 =
  33. 33.79 − 29 =
  34. 34.30 + 29 =
  35. 35.96 − 29 =
  36. 36.21 + 9 =
  37. 37.66 + 19 =
  38. 38.106 − 29 =
  39. 39.784 − 99 =
  40. 40.367 + 99 =

Answer key

  1. 85
  2. 71
  3. 591
  4. 89
  5. 79
  6. 688
  7. 16
  8. 25
  9. 35
  10. 38
  11. 33
  12. 166
  13. 724
  14. 25
  15. 39
  16. 91
  17. 845
  18. 61
  19. 70
  20. 733
  21. 13
  22. 5
  23. 39
  24. 63
  25. 390
  26. 34
  27. 43
  28. 40
  29. 260
  30. 47
  31. 374
  32. 22
  33. 50
  34. 59
  35. 67
  36. 30
  37. 85
  38. 77
  39. 685
  40. 466

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