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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 424 · 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. 1.317? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.5?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?019 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 73 and take away the sum of its digits. What do you get?
  5. 5.1?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.622? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.361? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.6?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?230 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 83 and take away the sum of its digits. What do you get?
  11. 11.Take 32 and take away the sum of its digits. What do you get?
  12. 12.?875 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.2?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.5?9 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. 16.2?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 80 and take away the sum of its digits. What do you get?
  18. 18.826? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 43 and take away the sum of its digits. What do you get?
  20. 20.3?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 39 and take away the sum of its digits. What do you get?
  22. 22.6?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.4?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.5?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?383 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.266? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.4?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?923 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.2?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 66 and take away the sum of its digits. What do you get?
  32. 32.?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 36 and take away the sum of its digits. What do you get?
  34. 34.Take 93 and take away the sum of its digits. What do you get?
  35. 35.?233 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.86?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?704 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.309? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.660? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 7
  2. 4
  3. 8
  4. 63
  5. 4
  6. 8
  7. 8
  8. 8
  9. 4
  10. 72
  11. 27
  12. 7
  13. 1
  14. 4
  15. 45
  16. 7
  17. 72
  18. 2
  19. 36
  20. 5
  21. 27
  22. 9
  23. 6
  24. 6
  25. 4
  26. 4
  27. 6
  28. 5
  29. 4
  30. 6
  31. 54
  32. 3
  33. 27
  34. 81
  35. 1
  36. 7
  37. 2
  38. 7
  39. 6
  40. 6

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