← 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 665 · 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. 1.306 + 99 =
  2. 2.21 + 19 =
  3. 3.43 + 19 =
  4. 4.66 + 29 =
  5. 5.25 − 19 =
  6. 6.52 + 29 =
  7. 7.56 − 9 =
  8. 8.77 + 9 =
  9. 9.28 − 9 =
  10. 10.67 − 9 =
  11. 11.383 − 99 =
  12. 12.56 + 19 =
  13. 13.752 + 99 =
  14. 14.25 + 29 =
  15. 15.48 + 19 =
  16. 16.93 − 29 =
  17. 17.28 − 19 =
  18. 18.283 + 99 =
  19. 19.30 + 9 =
  20. 20.59 + 9 =
  21. 21.445 + 99 =
  22. 22.42 + 29 =
  23. 23.80 + 9 =
  24. 24.624 + 99 =
  25. 25.22 − 19 =
  26. 26.44 + 19 =
  27. 27.42 + 19 =
  28. 28.47 + 9 =
  29. 29.71 + 19 =
  30. 30.100 − 29 =
  31. 31.75 − 19 =
  32. 32.65 + 29 =
  33. 33.46 + 9 =
  34. 34.87 − 19 =
  35. 35.717 − 99 =
  36. 36.345 − 99 =
  37. 37.606 − 99 =
  38. 38.37 − 29 =
  39. 39.15 − 9 =
  40. 40.62 + 29 =

Answer key

  1. 405
  2. 40
  3. 62
  4. 95
  5. 6
  6. 81
  7. 47
  8. 86
  9. 19
  10. 58
  11. 284
  12. 75
  13. 851
  14. 54
  15. 67
  16. 64
  17. 9
  18. 382
  19. 39
  20. 68
  21. 544
  22. 71
  23. 89
  24. 723
  25. 3
  26. 63
  27. 61
  28. 56
  29. 90
  30. 71
  31. 56
  32. 94
  33. 55
  34. 68
  35. 618
  36. 246
  37. 507
  38. 8
  39. 6
  40. 91

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