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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 884 · 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.?113 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 47 and take away the sum of its digits. What do you get?
  3. 3.718? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?528 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.8?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.1?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 62 and take away the sum of its digits. What do you get?
  8. 8.Take 94 and take away the sum of its digits. What do you get?
  9. 9.Take 37 and take away the sum of its digits. What do you get?
  10. 10.?006 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.29?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.843? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 72 and take away the sum of its digits. What do you get?
  14. 14.Take 20 and take away the sum of its digits. What do you get?
  15. 15.8?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.9?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 66 and take away the sum of its digits. What do you get?
  18. 18.161? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 95 and take away the sum of its digits. What do you get?
  21. 21.11?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.273? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.237? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.8?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.18?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.59?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.32?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.557? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 22 and take away the sum of its digits. What do you get?
  30. 30.Take 91 and take away the sum of its digits. What do you get?
  31. 31.?143 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.22?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.860? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.1?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.349? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 36 and take away the sum of its digits. What do you get?
  39. 39.Take 75 and take away the sum of its digits. What do you get?
  40. 40.16?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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