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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 385 · 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. 1.156? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.59?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 94 and take away the sum of its digits. What do you get?
  6. 6.60?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.642? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?039 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 57 and take away the sum of its digits. What do you get?
  10. 10.?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.88?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.40?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 74 and take away the sum of its digits. What do you get?
  15. 15.Take 23 and take away the sum of its digits. What do you get?
  16. 16.3?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.10?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.27?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.2?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?894 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.21?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.69?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 89 and take away the sum of its digits. What do you get?
  25. 25.Take 72 and take away the sum of its digits. What do you get?
  26. 26.7?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 96 and take away the sum of its digits. What do you get?
  28. 28.55?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.61?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?025 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.27?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.31?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 39 and take away the sum of its digits. What do you get?
  35. 35.?712 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 31 and take away the sum of its digits. What do you get?
  38. 38.Take 46 and take away the sum of its digits. What do you get?
  39. 39.38? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?515 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. 1
  3. 4
  4. 3
  5. 81
  6. 4
  7. 6
  8. 6
  9. 45
  10. 6
  11. 9
  12. 2
  13. 5
  14. 63
  15. 18
  16. 3
  17. 7
  18. 2
  19. 9
  20. 6
  21. 4
  22. 1
  23. 8
  24. 72
  25. 63
  26. 4
  27. 81
  28. 4
  29. 6
  30. 2
  31. 9
  32. 7
  33. 8
  34. 27
  35. 8
  36. 9
  37. 27
  38. 36
  39. 7
  40. 7

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