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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 702 · 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. 1.14?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.87?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 71 and take away the sum of its digits. What do you get?
  4. 4.Take 85 and take away the sum of its digits. What do you get?
  5. 5.?367 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.6?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?23 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.Take 91 and take away the sum of its digits. What do you get?
  11. 11.Take 88 and take away the sum of its digits. What do you get?
  12. 12.?560 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 93 and take away the sum of its digits. What do you get?
  15. 15.Take 13 and take away the sum of its digits. What do you get?
  16. 16.555? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.823? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.746? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 69 and take away the sum of its digits. What do you get?
  20. 20.Take 44 and take away the sum of its digits. What do you get?
  21. 21.50?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 87 and take away the sum of its digits. What do you get?
  23. 23.?500 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?840 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 17 and take away the sum of its digits. What do you get?
  26. 26.630? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 25 and take away the sum of its digits. What do you get?
  28. 28.?958 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 11 and take away the sum of its digits. What do you get?
  30. 30.Take 90 and take away the sum of its digits. What do you get?
  31. 31.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.710? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?507 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.96? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.536? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.10?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.1?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.51?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.421? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 41 and take away the sum of its digits. What do you get?

Answer key

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

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