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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 155 · 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 32 and take away the sum of its digits. What do you get?
  2. 2.816? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.67? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?604 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 28 and take away the sum of its digits. What do you get?
  6. 6.Take 60 and take away the sum of its digits. What do you get?
  7. 7.888? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?980 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.70?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.56? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.97? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.704? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 72 and take away the sum of its digits. What do you get?
  14. 14.39?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?022 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.3?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.286? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.635? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?381 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?548 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 56 and take away the sum of its digits. What do you get?
  22. 22.?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.690? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.181? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.427? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 97 and take away the sum of its digits. What do you get?
  27. 27.Take 34 and take away the sum of its digits. What do you get?
  28. 28.?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?700 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?205 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?602 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?146 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.60?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 55 and take away the sum of its digits. What do you get?
  35. 35.?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.135? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?014 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.299? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 35 and take away the sum of its digits. What do you get?
  40. 40.Take 39 and take away the sum of its digits. What do you get?

Answer key

  1. 27
  2. 3
  3. 5
  4. 8
  5. 18
  6. 54
  7. 3
  8. 1
  9. 4
  10. 7
  11. 2
  12. 7
  13. 63
  14. 5
  15. 5
  16. 8
  17. 2
  18. 4
  19. 6
  20. 1
  21. 45
  22. 6
  23. 3
  24. 8
  25. 5
  26. 81
  27. 27
  28. 3
  29. 2
  30. 2
  31. 1
  32. 7
  33. 3
  34. 45
  35. 1
  36. 9
  37. 4
  38. 7
  39. 27
  40. 27

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