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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 710 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.28? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.2?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.82?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?224 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 55 and take away the sum of its digits. What do you get?
  7. 7.86?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.894? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.816? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.239? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.793? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.622? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 23 and take away the sum of its digits. What do you get?
  14. 14.7?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 57 and take away the sum of its digits. What do you get?
  16. 16.76?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 41 and take away the sum of its digits. What do you get?
  18. 18.75? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 11 and take away the sum of its digits. What do you get?
  20. 20.?407 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 89 and take away the sum of its digits. What do you get?
  22. 22.202? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?282 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.90? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.45?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?510 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.3?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.88? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?212 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.10?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 86 and take away the sum of its digits. What do you get?
  32. 32.?560 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.2?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?303 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 44 and take away the sum of its digits. What do you get?
  36. 36.627? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?197 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?858 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?797 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 8
  2. 2
  3. 1
  4. 1
  5. 8
  6. 45
  7. 5
  8. 6
  9. 3
  10. 4
  11. 8
  12. 8
  13. 18
  14. 5
  15. 45
  16. 6
  17. 36
  18. 6
  19. 9
  20. 7
  21. 72
  22. 5
  23. 6
  24. 9
  25. 6
  26. 3
  27. 3
  28. 2
  29. 4
  30. 6
  31. 72
  32. 7
  33. 1
  34. 3
  35. 36
  36. 3
  37. 1
  38. 9
  39. 6
  40. 4

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