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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 786 · 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. 1.3?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.74? 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. 4.17?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.692? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.23?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.47?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?280 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.43?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 19 and take away the sum of its digits. What do you get?
  11. 11.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.15?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.67?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.16?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.561? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 55 and take away the sum of its digits. What do you get?
  20. 20.?335 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.34?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.42?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 46 and take away the sum of its digits. What do you get?
  24. 24.70?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?902 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?302 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.12?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 27 and take away the sum of its digits. What do you get?
  29. 29.?988 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.833? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 77 and take away the sum of its digits. What do you get?
  32. 32.?487 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.31?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.44?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.484? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.6?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?344 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.5?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.8?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?430 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. 7
  3. 63
  4. 1
  5. 1
  6. 7
  7. 7
  8. 8
  9. 8
  10. 9
  11. 6
  12. 6
  13. 3
  14. 1
  15. 7
  16. 3
  17. 6
  18. 1
  19. 45
  20. 7
  21. 4
  22. 9
  23. 36
  24. 4
  25. 7
  26. 4
  27. 3
  28. 18
  29. 2
  30. 4
  31. 63
  32. 8
  33. 3
  34. 4
  35. 2
  36. 1
  37. 7
  38. 9
  39. 1
  40. 2

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