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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 117 · 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.?938 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 92 and take away the sum of its digits. What do you get?
  3. 3.?100 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.77?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.57?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 11 and take away the sum of its digits. What do you get?
  7. 7.3?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 95 and take away the sum of its digits. What do you get?
  9. 9.Take 18 and take away the sum of its digits. What do you get?
  10. 10.31? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 24 and take away the sum of its digits. What do you get?
  12. 12.?537 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.700? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.56? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.572? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 57 and take away the sum of its digits. What do you get?
  18. 18.?627 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.1?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.4?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.13?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.5?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?185 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?994 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?973 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 36 and take away the sum of its digits. What do you get?
  28. 28.63?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?633 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 43 and take away the sum of its digits. What do you get?
  31. 31.Take 80 and take away the sum of its digits. What do you get?
  32. 32.?240 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.81?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 79 and take away the sum of its digits. What do you get?
  36. 36.Take 14 and take away the sum of its digits. What do you get?
  37. 37.Take 56 and take away the sum of its digits. What do you get?
  38. 38.133? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.3?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 17 and take away the sum of its digits. What do you get?

Answer key

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

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