← 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 872 · 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. 1.73 + 9 =
  2. 2.39 − 19 =
  3. 3.23 + 29 =
  4. 4.24 + 19 =
  5. 5.61 − 9 =
  6. 6.63 − 19 =
  7. 7.573 − 99 =
  8. 8.53 − 9 =
  9. 9.66 + 19 =
  10. 10.37 + 9 =
  11. 11.30 + 29 =
  12. 12.72 + 29 =
  13. 13.66 + 9 =
  14. 14.37 − 9 =
  15. 15.220 + 99 =
  16. 16.96 − 19 =
  17. 17.73 − 19 =
  18. 18.61 − 29 =
  19. 19.530 + 99 =
  20. 20.35 + 29 =
  21. 21.611 + 99 =
  22. 22.62 − 29 =
  23. 23.103 − 29 =
  24. 24.58 − 9 =
  25. 25.79 − 29 =
  26. 26.86 − 9 =
  27. 27.53 − 19 =
  28. 28.90 − 29 =
  29. 29.69 − 19 =
  30. 30.29 − 19 =
  31. 31.20 + 9 =
  32. 32.47 + 29 =
  33. 33.796 + 99 =
  34. 34.56 + 9 =
  35. 35.333 − 99 =
  36. 36.104 − 29 =
  37. 37.52 + 19 =
  38. 38.32 − 9 =
  39. 39.38 + 9 =
  40. 40.38 + 19 =

Answer key

  1. 82
  2. 20
  3. 52
  4. 43
  5. 52
  6. 44
  7. 474
  8. 44
  9. 85
  10. 46
  11. 59
  12. 101
  13. 75
  14. 28
  15. 319
  16. 77
  17. 54
  18. 32
  19. 629
  20. 64
  21. 710
  22. 33
  23. 74
  24. 49
  25. 50
  26. 77
  27. 34
  28. 61
  29. 50
  30. 10
  31. 29
  32. 76
  33. 895
  34. 65
  35. 234
  36. 75
  37. 71
  38. 23
  39. 47
  40. 57

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