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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 114 · 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.?323 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 24 and take away the sum of its digits. What do you get?
  3. 3.Take 55 and take away the sum of its digits. What do you get?
  4. 4.?120 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.4?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 64 and take away the sum of its digits. What do you get?
  7. 7.Take 42 and take away the sum of its digits. What do you get?
  8. 8.8?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.604? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.47?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 77 and take away the sum of its digits. What do you get?
  12. 12.?884 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.13?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?226 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 28 and take away the sum of its digits. What do you get?
  16. 16.4?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.657? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 23 and take away the sum of its digits. What do you get?
  19. 19.?413 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.79?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.6?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.6?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.86?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 38 and take away the sum of its digits. What do you get?
  25. 25.60?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.72?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.46?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?822 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.332? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.68?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.9?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.7?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.35?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?580 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?787 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?760 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.8?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.4?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 17 and take away the sum of its digits. What do you get?
  40. 40.Take 81 and take away the sum of its digits. What do you get?

Answer key

  1. 1
  2. 18
  3. 45
  4. 6
  5. 8
  6. 54
  7. 36
  8. 3
  9. 8
  10. 1
  11. 63
  12. 7
  13. 8
  14. 8
  15. 18
  16. 9
  17. 9
  18. 18
  19. 1
  20. 4
  21. 8
  22. 3
  23. 7
  24. 27
  25. 8
  26. 6
  27. 7
  28. 6
  29. 1
  30. 5
  31. 7
  32. 5
  33. 7
  34. 5
  35. 5
  36. 5
  37. 9
  38. 3
  39. 9
  40. 72

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