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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 550 · 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. 1.837? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 15 and take away the sum of its digits. What do you get?
  3. 3.Take 23 and take away the sum of its digits. What do you get?
  4. 4.?713 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 59 and take away the sum of its digits. What do you get?
  6. 6.60?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?586 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 73 and take away the sum of its digits. What do you get?
  9. 9.894? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?267 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 36 and take away the sum of its digits. What do you get?
  12. 12.142? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.45?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.26?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?734 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?124 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?845 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.2?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 87 and take away the sum of its digits. What do you get?
  21. 21.16?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 63 and take away the sum of its digits. What do you get?
  23. 23.Take 30 and take away the sum of its digits. What do you get?
  24. 24.Take 52 and take away the sum of its digits. What do you get?
  25. 25.3?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.27? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 13 and take away the sum of its digits. What do you get?
  28. 28.241? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?615 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.5?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.5?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.46?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?314 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.73?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.5?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?310 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?305 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.67?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.340? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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