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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 940 · 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. 1.220? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.802? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.3?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.592? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?457 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 82 and take away the sum of its digits. What do you get?
  8. 8.Take 48 and take away the sum of its digits. What do you get?
  9. 9.81?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 35 and take away the sum of its digits. What do you get?
  11. 11.?415 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.18?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 33 and take away the sum of its digits. What do you get?
  14. 14.?584 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 15 and take away the sum of its digits. What do you get?
  16. 16.4?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 52 and take away the sum of its digits. What do you get?
  19. 19.5?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 72 and take away the sum of its digits. What do you get?
  21. 21.4?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 89 and take away the sum of its digits. What do you get?
  23. 23.Take 32 and take away the sum of its digits. What do you get?
  24. 24.?550 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.1?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.41?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 57 and take away the sum of its digits. What do you get?
  28. 28.48?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?651 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.575? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.29?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.6?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?159 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.5?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 92 and take away the sum of its digits. What do you get?
  36. 36.Take 75 and take away the sum of its digits. What do you get?
  37. 37.390? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?231 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.76? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.46?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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