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Adding 9, 19 and 99 Mental Maths Worksheet

Mental maths lesson 4: Add and take away 9, 19 and 99 · Set 331 · 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. 1.39 + 19 =
  2. 2.43 + 19 =
  3. 3.59 − 9 =
  4. 4.22 + 29 =
  5. 5.41 + 9 =
  6. 6.15 + 19 =
  7. 7.65 − 29 =
  8. 8.345 + 99 =
  9. 9.375 − 99 =
  10. 10.24 + 29 =
  11. 11.13 + 29 =
  12. 12.713 + 99 =
  13. 13.280 − 99 =
  14. 14.86 − 19 =
  15. 15.414 + 99 =
  16. 16.52 − 19 =
  17. 17.12 + 19 =
  18. 18.105 − 29 =
  19. 19.58 + 29 =
  20. 20.33 − 9 =
  21. 21.39 − 9 =
  22. 22.59 + 9 =
  23. 23.335 + 99 =
  24. 24.182 + 99 =
  25. 25.238 + 99 =
  26. 26.31 − 9 =
  27. 27.34 + 19 =
  28. 28.26 + 9 =
  29. 29.606 + 99 =
  30. 30.45 − 9 =
  31. 31.12 + 9 =
  32. 32.50 + 19 =
  33. 33.21 + 29 =
  34. 34.17 + 19 =
  35. 35.582 + 99 =
  36. 36.237 + 99 =
  37. 37.38 − 19 =
  38. 38.49 + 19 =
  39. 39.733 + 99 =
  40. 40.60 + 9 =

Answer key

  1. 58
  2. 62
  3. 50
  4. 51
  5. 50
  6. 34
  7. 36
  8. 444
  9. 276
  10. 53
  11. 42
  12. 812
  13. 181
  14. 67
  15. 513
  16. 33
  17. 31
  18. 76
  19. 87
  20. 24
  21. 30
  22. 68
  23. 434
  24. 281
  25. 337
  26. 22
  27. 53
  28. 35
  29. 705
  30. 36
  31. 21
  32. 69
  33. 50
  34. 36
  35. 681
  36. 336
  37. 19
  38. 68
  39. 832
  40. 69

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