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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 147 · 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. 1.6?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.89? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.73?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.4?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 38 and take away the sum of its digits. What do you get?
  6. 6.Take 96 and take away the sum of its digits. What do you get?
  7. 7.6?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.82?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.84?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?352 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 48 and take away the sum of its digits. What do you get?
  13. 13.2?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.73?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.428? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 73 and take away the sum of its digits. What do you get?
  17. 17.Take 52 and take away the sum of its digits. What do you get?
  18. 18.?376 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 39 and take away the sum of its digits. What do you get?
  20. 20.11?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.8?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.8?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?015 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 40 and take away the sum of its digits. What do you get?
  25. 25.81?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.402? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 83 and take away the sum of its digits. What do you get?
  28. 28.?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.850? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 62 and take away the sum of its digits. What do you get?
  31. 31.374? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.16?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?400 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 49 and take away the sum of its digits. What do you get?
  35. 35.Take 91 and take away the sum of its digits. What do you get?
  36. 36.?056 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 84 and take away the sum of its digits. What do you get?
  38. 38.856? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?600 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.591? 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. 1
  3. 8
  4. 5
  5. 27
  6. 81
  7. 9
  8. 9
  9. 8
  10. 3
  11. 8
  12. 36
  13. 6
  14. 2
  15. 4
  16. 63
  17. 45
  18. 2
  19. 27
  20. 1
  21. 5
  22. 2
  23. 3
  24. 36
  25. 5
  26. 3
  27. 72
  28. 2
  29. 5
  30. 54
  31. 4
  32. 8
  33. 5
  34. 36
  35. 81
  36. 7
  37. 72
  38. 8
  39. 3
  40. 3

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