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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 938 · 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. 1.349? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?245 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 67 and take away the sum of its digits. What do you get?
  4. 4.Take 77 and take away the sum of its digits. What do you get?
  5. 5.57? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?483 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.788? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 71 and take away the sum of its digits. What do you get?
  9. 9.7?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?258 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 64 and take away the sum of its digits. What do you get?
  12. 12.?685 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.10?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.53?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.63?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.6?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.8?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.450? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.80?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.24?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?597 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 99 and take away the sum of its digits. What do you get?
  24. 24.?721 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.500? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 45 and take away the sum of its digits. What do you get?
  27. 27.5?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 93 and take away the sum of its digits. What do you get?
  29. 29.Take 12 and take away the sum of its digits. What do you get?
  30. 30.45?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.56?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 32 and take away the sum of its digits. What do you get?
  33. 33.?818 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 68 and take away the sum of its digits. What do you get?
  36. 36.Take 46 and take away the sum of its digits. What do you get?
  37. 37.?057 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?330 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?897 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.6?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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