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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 277 · 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.?020 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?997 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?034 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.34?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?086 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.889? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 34 and take away the sum of its digits. What do you get?
  9. 9.?226 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 22 and take away the sum of its digits. What do you get?
  11. 11.Take 98 and take away the sum of its digits. What do you get?
  12. 12.271? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 18 and take away the sum of its digits. What do you get?
  14. 14.3?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 23 and take away the sum of its digits. What do you get?
  16. 16.Take 88 and take away the sum of its digits. What do you get?
  17. 17.?635 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.11?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.205? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 17 and take away the sum of its digits. What do you get?
  21. 21.439? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 60 and take away the sum of its digits. What do you get?
  23. 23.209? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.6?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?518 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.18?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.4?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?525 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.117? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 52 and take away the sum of its digits. What do you get?
  31. 31.Take 81 and take away the sum of its digits. What do you get?
  32. 32.341? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.433? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.243? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 29 and take away the sum of its digits. What do you get?
  36. 36.?514 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.47?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.247? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.609? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?597 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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