← 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 146 · 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. 1.212 + 99 =
  2. 2.34 + 9 =
  3. 3.700 + 99 =
  4. 4.45 + 19 =
  5. 5.63 − 9 =
  6. 6.70 + 29 =
  7. 7.18 + 19 =
  8. 8.219 − 99 =
  9. 9.308 + 99 =
  10. 10.74 + 29 =
  11. 11.23 − 19 =
  12. 12.57 + 29 =
  13. 13.98 − 29 =
  14. 14.19 + 19 =
  15. 15.20 + 19 =
  16. 16.42 − 29 =
  17. 17.30 − 9 =
  18. 18.58 + 9 =
  19. 19.59 − 19 =
  20. 20.54 + 29 =
  21. 21.40 − 29 =
  22. 22.82 − 9 =
  23. 23.60 − 9 =
  24. 24.76 + 9 =
  25. 25.31 + 9 =
  26. 26.765 − 99 =
  27. 27.70 + 9 =
  28. 28.798 − 99 =
  29. 29.674 − 99 =
  30. 30.50 − 19 =
  31. 31.49 + 29 =
  32. 32.424 − 99 =
  33. 33.27 − 19 =
  34. 34.60 − 19 =
  35. 35.208 + 99 =
  36. 36.696 + 99 =
  37. 37.804 − 99 =
  38. 38.398 + 99 =
  39. 39.880 − 99 =
  40. 40.38 + 29 =

Answer key

  1. 311
  2. 43
  3. 799
  4. 64
  5. 54
  6. 99
  7. 37
  8. 120
  9. 407
  10. 103
  11. 4
  12. 86
  13. 69
  14. 38
  15. 39
  16. 13
  17. 21
  18. 67
  19. 40
  20. 83
  21. 11
  22. 73
  23. 51
  24. 85
  25. 40
  26. 666
  27. 79
  28. 699
  29. 575
  30. 31
  31. 78
  32. 325
  33. 8
  34. 41
  35. 307
  36. 795
  37. 705
  38. 497
  39. 781
  40. 67

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