← 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 482 · 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. 1.327 + 99 =
  2. 2.29 + 9 =
  3. 3.75 − 9 =
  4. 4.54 + 19 =
  5. 5.72 + 19 =
  6. 6.97 − 19 =
  7. 7.34 − 9 =
  8. 8.39 − 29 =
  9. 9.76 + 19 =
  10. 10.53 − 9 =
  11. 11.45 − 19 =
  12. 12.63 − 19 =
  13. 13.68 + 9 =
  14. 14.585 + 99 =
  15. 15.34 + 19 =
  16. 16.41 − 19 =
  17. 17.50 − 9 =
  18. 18.57 − 9 =
  19. 19.655 − 99 =
  20. 20.25 + 29 =
  21. 21.70 + 9 =
  22. 22.55 − 29 =
  23. 23.109 − 29 =
  24. 24.33 − 29 =
  25. 25.27 − 9 =
  26. 26.45 − 9 =
  27. 27.75 + 19 =
  28. 28.45 − 29 =
  29. 29.37 + 9 =
  30. 30.29 + 19 =
  31. 31.88 − 29 =
  32. 32.108 − 29 =
  33. 33.639 − 99 =
  34. 34.449 − 99 =
  35. 35.271 − 99 =
  36. 36.47 + 19 =
  37. 37.22 + 19 =
  38. 38.67 + 9 =
  39. 39.135 + 99 =
  40. 40.77 − 29 =

Answer key

  1. 426
  2. 38
  3. 66
  4. 73
  5. 91
  6. 78
  7. 25
  8. 10
  9. 95
  10. 44
  11. 26
  12. 44
  13. 77
  14. 684
  15. 53
  16. 22
  17. 41
  18. 48
  19. 556
  20. 54
  21. 79
  22. 26
  23. 80
  24. 4
  25. 18
  26. 36
  27. 94
  28. 16
  29. 46
  30. 48
  31. 59
  32. 79
  33. 540
  34. 350
  35. 172
  36. 66
  37. 41
  38. 76
  39. 234
  40. 48

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