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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 326 · 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.Take 27 and take away the sum of its digits. What do you get?
  2. 2.?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.550? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?143 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?403 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 68 and take away the sum of its digits. What do you get?
  7. 7.Take 25 and take away the sum of its digits. What do you get?
  8. 8.Take 46 and take away the sum of its digits. What do you get?
  9. 9.?663 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.295? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.32?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 16 and take away the sum of its digits. What do you get?
  13. 13.Take 35 and take away the sum of its digits. What do you get?
  14. 14.1?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 53 and take away the sum of its digits. What do you get?
  16. 16.?885 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 74 and take away the sum of its digits. What do you get?
  18. 18.2?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?814 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.559? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?957 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 58 and take away the sum of its digits. What do you get?
  23. 23.Take 41 and take away the sum of its digits. What do you get?
  24. 24.Take 33 and take away the sum of its digits. What do you get?
  25. 25.351? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.4?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.31?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 70 and take away the sum of its digits. What do you get?
  31. 31.Take 75 and take away the sum of its digits. What do you get?
  32. 32.344? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.1?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?352 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.3?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?968 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 49 and take away the sum of its digits. What do you get?
  38. 38.23?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?112 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.4?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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