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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 132 · 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. 1.498? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.2?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 76 and take away the sum of its digits. What do you get?
  4. 4.572? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.4?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?356 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.638? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 48 and take away the sum of its digits. What do you get?
  10. 10.Take 82 and take away the sum of its digits. What do you get?
  11. 11.Take 21 and take away the sum of its digits. What do you get?
  12. 12.726? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 88 and take away the sum of its digits. What do you get?
  14. 14.8?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 46 and take away the sum of its digits. What do you get?
  16. 16.Take 17 and take away the sum of its digits. What do you get?
  17. 17.Take 58 and take away the sum of its digits. What do you get?
  18. 18.65?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 73 and take away the sum of its digits. What do you get?
  20. 20.Take 92 and take away the sum of its digits. What do you get?
  21. 21.54? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 53 and take away the sum of its digits. What do you get?
  23. 23.Take 91 and take away the sum of its digits. What do you get?
  24. 24.279? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 75 and take away the sum of its digits. What do you get?
  26. 26.?161 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?471 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.6?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.34?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 11 and take away the sum of its digits. What do you get?
  31. 31.?636 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?932 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.8?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.495? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?212 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?235 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.604? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?740 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.2?94 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. 7
  3. 63
  4. 4
  5. 4
  6. 4
  7. 7
  8. 1
  9. 36
  10. 72
  11. 18
  12. 3
  13. 72
  14. 6
  15. 36
  16. 9
  17. 45
  18. 9
  19. 63
  20. 81
  21. 9
  22. 45
  23. 81
  24. 9
  25. 63
  26. 1
  27. 6
  28. 8
  29. 8
  30. 9
  31. 3
  32. 4
  33. 1
  34. 9
  35. 6
  36. 4
  37. 8
  38. 8
  39. 7
  40. 3

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