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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 31 · 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.Take 67 and take away the sum of its digits. What do you get?
  2. 2.474? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?456 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.81?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 95 and take away the sum of its digits. What do you get?
  6. 6.Take 55 and take away the sum of its digits. What do you get?
  7. 7.?076 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.83?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?200 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.693? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.19?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.746? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?222 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.1?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.31?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.4?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.74?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.2?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.22? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?713 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 59 and take away the sum of its digits. What do you get?
  24. 24.204? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?039 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?309 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.852? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 42 and take away the sum of its digits. What do you get?
  29. 29.Take 89 and take away the sum of its digits. What do you get?
  30. 30.Take 44 and take away the sum of its digits. What do you get?
  31. 31.894? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 27 and take away the sum of its digits. What do you get?
  33. 33.Take 70 and take away the sum of its digits. What do you get?
  34. 34.?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?376 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?790 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.184? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 23 and take away the sum of its digits. What do you get?
  39. 39.?242 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.6?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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