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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 286 · 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. 1.128? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?901 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.224? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.88?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.53?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 63 and take away the sum of its digits. What do you get?
  8. 8.28?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.89?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.23?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.30? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.19?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 15 and take away the sum of its digits. What do you get?
  15. 15.Take 39 and take away the sum of its digits. What do you get?
  16. 16.?991 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.15?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.1?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 80 and take away the sum of its digits. What do you get?
  21. 21.4?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 75 and take away the sum of its digits. What do you get?
  23. 23.Take 35 and take away the sum of its digits. What do you get?
  24. 24.445? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.5?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.48?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.6?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?318 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.7?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?358 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 25 and take away the sum of its digits. What do you get?
  33. 33.?589 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 45 and take away the sum of its digits. What do you get?
  35. 35.7?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?149 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 60 and take away the sum of its digits. What do you get?
  39. 39.310? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 89 and take away the sum of its digits. What do you get?

Answer key

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

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