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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 417 · 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. 1.63?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 53 and take away the sum of its digits. What do you get?
  3. 3.226? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 83 and take away the sum of its digits. What do you get?
  6. 6.?251 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?235 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.70?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.64?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 38 and take away the sum of its digits. What do you get?
  12. 12.Take 95 and take away the sum of its digits. What do you get?
  13. 13.?582 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 22 and take away the sum of its digits. What do you get?
  15. 15.?583 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 54 and take away the sum of its digits. What do you get?
  17. 17.162? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 19 and take away the sum of its digits. What do you get?
  19. 19.635? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 41 and take away the sum of its digits. What do you get?
  21. 21.Take 71 and take away the sum of its digits. What do you get?
  22. 22.?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.1?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?561 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 33 and take away the sum of its digits. What do you get?
  27. 27.67?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 18 and take away the sum of its digits. What do you get?
  29. 29.20?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.4?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 57 and take away the sum of its digits. What do you get?
  32. 32.581? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 64 and take away the sum of its digits. What do you get?
  34. 34.3?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.37?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 56 and take away the sum of its digits. What do you get?
  37. 37.472? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?812 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?528 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.26?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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