← 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 974 · 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. 1.550 + 99 =
  2. 2.13 + 19 =
  3. 3.47 − 9 =
  4. 4.44 + 29 =
  5. 5.42 + 29 =
  6. 6.45 − 19 =
  7. 7.34 − 19 =
  8. 8.114 + 99 =
  9. 9.54 + 19 =
  10. 10.27 + 29 =
  11. 11.101 − 29 =
  12. 12.85 − 29 =
  13. 13.306 + 99 =
  14. 14.168 − 99 =
  15. 15.89 − 9 =
  16. 16.523 − 99 =
  17. 17.12 + 19 =
  18. 18.34 + 29 =
  19. 19.48 + 9 =
  20. 20.52 + 19 =
  21. 21.40 − 19 =
  22. 22.15 + 29 =
  23. 23.77 + 9 =
  24. 24.28 + 19 =
  25. 25.410 + 99 =
  26. 26.454 − 99 =
  27. 27.620 − 99 =
  28. 28.19 + 9 =
  29. 29.26 + 19 =
  30. 30.62 + 29 =
  31. 31.154 + 99 =
  32. 32.66 + 19 =
  33. 33.267 − 99 =
  34. 34.759 + 99 =
  35. 35.74 − 19 =
  36. 36.37 + 29 =
  37. 37.222 + 99 =
  38. 38.70 − 29 =
  39. 39.14 + 29 =
  40. 40.16 + 9 =

Answer key

  1. 649
  2. 32
  3. 38
  4. 73
  5. 71
  6. 26
  7. 15
  8. 213
  9. 73
  10. 56
  11. 72
  12. 56
  13. 405
  14. 69
  15. 80
  16. 424
  17. 31
  18. 63
  19. 57
  20. 71
  21. 21
  22. 44
  23. 86
  24. 47
  25. 509
  26. 355
  27. 521
  28. 28
  29. 45
  30. 91
  31. 253
  32. 85
  33. 168
  34. 858
  35. 55
  36. 66
  37. 321
  38. 41
  39. 43
  40. 25

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