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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 280 · 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. 1.5?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?476 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.176? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.2?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?096 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 26 and take away the sum of its digits. What do you get?
  7. 7.Take 32 and take away the sum of its digits. What do you get?
  8. 8.Take 15 and take away the sum of its digits. What do you get?
  9. 9.Take 25 and take away the sum of its digits. What do you get?
  10. 10.Take 64 and take away the sum of its digits. What do you get?
  11. 11.448? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.87?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.689? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.6?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?546 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 33 and take away the sum of its digits. What do you get?
  17. 17.Take 87 and take away the sum of its digits. What do you get?
  18. 18.?829 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.8?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.2?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 22 and take away the sum of its digits. What do you get?
  22. 22.?044 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.5?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?287 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.55?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.6?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.5?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?303 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.10?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 17 and take away the sum of its digits. What do you get?
  31. 31.3?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 13 and take away the sum of its digits. What do you get?
  33. 33.404? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 71 and take away the sum of its digits. What do you get?
  35. 35.Take 45 and take away the sum of its digits. What do you get?
  36. 36.?780 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?528 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.30?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.1?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 58 and take away the sum of its digits. What do you get?

Answer key

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

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