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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 386 · 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.?764 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.1?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 86 and take away the sum of its digits. What do you get?
  5. 5.68?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?824 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.13?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.426? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.695? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 67 and take away the sum of its digits. What do you get?
  11. 11.6?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 11 and take away the sum of its digits. What do you get?
  13. 13.1?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.845? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.6?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.89?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.67? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?632 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?779 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 58 and take away the sum of its digits. What do you get?
  22. 22.Take 72 and take away the sum of its digits. What do you get?
  23. 23.3?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.747? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.31?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?384 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.630? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.2?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.557? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.13?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 88 and take away the sum of its digits. What do you get?
  34. 34.743? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.374? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 76 and take away the sum of its digits. What do you get?
  37. 37.?943 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?300 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 99 and take away the sum of its digits. What do you get?

Answer key

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

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