← 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 852 · 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. 1.50 + 29 =
  2. 2.14 + 19 =
  3. 3.43 + 19 =
  4. 4.225 − 99 =
  5. 5.79 + 29 =
  6. 6.69 − 19 =
  7. 7.31 + 29 =
  8. 8.69 − 9 =
  9. 9.77 − 9 =
  10. 10.818 − 99 =
  11. 11.52 + 29 =
  12. 12.86 − 9 =
  13. 13.269 − 99 =
  14. 14.75 + 19 =
  15. 15.32 + 29 =
  16. 16.28 + 29 =
  17. 17.54 − 29 =
  18. 18.512 + 99 =
  19. 19.65 + 9 =
  20. 20.320 + 99 =
  21. 21.20 + 29 =
  22. 22.28 + 9 =
  23. 23.71 − 29 =
  24. 24.785 + 99 =
  25. 25.57 + 9 =
  26. 26.38 + 9 =
  27. 27.53 + 19 =
  28. 28.32 − 9 =
  29. 29.42 − 9 =
  30. 30.58 + 19 =
  31. 31.35 − 19 =
  32. 32.81 − 9 =
  33. 33.230 + 99 =
  34. 34.26 + 9 =
  35. 35.33 − 9 =
  36. 36.347 + 99 =
  37. 37.18 + 29 =
  38. 38.66 + 19 =
  39. 39.891 − 99 =
  40. 40.68 + 9 =

Answer key

  1. 79
  2. 33
  3. 62
  4. 126
  5. 108
  6. 50
  7. 60
  8. 60
  9. 68
  10. 719
  11. 81
  12. 77
  13. 170
  14. 94
  15. 61
  16. 57
  17. 25
  18. 611
  19. 74
  20. 419
  21. 49
  22. 37
  23. 42
  24. 884
  25. 66
  26. 47
  27. 72
  28. 23
  29. 33
  30. 77
  31. 16
  32. 72
  33. 329
  34. 35
  35. 24
  36. 446
  37. 47
  38. 85
  39. 792
  40. 77

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