← 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 115 · 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. 1.64 − 19 =
  2. 2.48 + 9 =
  3. 3.30 − 19 =
  4. 4.49 + 9 =
  5. 5.17 + 29 =
  6. 6.73 + 29 =
  7. 7.219 + 99 =
  8. 8.24 + 9 =
  9. 9.79 − 19 =
  10. 10.59 − 29 =
  11. 11.37 + 9 =
  12. 12.85 − 29 =
  13. 13.180 + 99 =
  14. 14.48 + 29 =
  15. 15.684 + 99 =
  16. 16.38 + 9 =
  17. 17.38 − 9 =
  18. 18.60 + 29 =
  19. 19.67 + 9 =
  20. 20.20 + 9 =
  21. 21.15 + 19 =
  22. 22.43 + 29 =
  23. 23.78 − 29 =
  24. 24.75 + 9 =
  25. 25.69 − 19 =
  26. 26.65 − 19 =
  27. 27.47 + 9 =
  28. 28.42 + 29 =
  29. 29.349 − 99 =
  30. 30.45 − 19 =
  31. 31.75 − 29 =
  32. 32.445 + 99 =
  33. 33.62 + 29 =
  34. 34.541 − 99 =
  35. 35.78 − 9 =
  36. 36.56 − 9 =
  37. 37.36 + 9 =
  38. 38.32 + 9 =
  39. 39.29 + 19 =
  40. 40.21 + 9 =

Answer key

  1. 45
  2. 57
  3. 11
  4. 58
  5. 46
  6. 102
  7. 318
  8. 33
  9. 60
  10. 30
  11. 46
  12. 56
  13. 279
  14. 77
  15. 783
  16. 47
  17. 29
  18. 89
  19. 76
  20. 29
  21. 34
  22. 72
  23. 49
  24. 84
  25. 50
  26. 46
  27. 56
  28. 71
  29. 250
  30. 26
  31. 46
  32. 544
  33. 91
  34. 442
  35. 69
  36. 47
  37. 45
  38. 41
  39. 48
  40. 30

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