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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 173 · 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. 1.57?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 23 and take away the sum of its digits. What do you get?
  3. 3.410? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.5?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.882? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.332? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.6?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.1?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 29 and take away the sum of its digits. What do you get?
  10. 10.?326 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 49 and take away the sum of its digits. What do you get?
  12. 12.Take 30 and take away the sum of its digits. What do you get?
  13. 13.Take 82 and take away the sum of its digits. What do you get?
  14. 14.28?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 83 and take away the sum of its digits. What do you get?
  16. 16.38?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.870? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.550? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 21 and take away the sum of its digits. What do you get?
  20. 20.Take 78 and take away the sum of its digits. What do you get?
  21. 21.?127 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.26?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.8?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 96 and take away the sum of its digits. What do you get?
  25. 25.?731 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 88 and take away the sum of its digits. What do you get?
  27. 27.Take 38 and take away the sum of its digits. What do you get?
  28. 28.Take 56 and take away the sum of its digits. What do you get?
  29. 29.6?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?525 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.729? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?233 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?475 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?537 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?969 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 20 and take away the sum of its digits. What do you get?
  37. 37.19?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.298? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.24?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.60?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 1
  2. 18
  3. 4
  4. 6
  5. 9
  6. 1
  7. 6
  8. 1
  9. 18
  10. 7
  11. 36
  12. 27
  13. 72
  14. 3
  15. 72
  16. 4
  17. 3
  18. 8
  19. 18
  20. 63
  21. 8
  22. 1
  23. 4
  24. 81
  25. 7
  26. 72
  27. 27
  28. 45
  29. 8
  30. 6
  31. 9
  32. 1
  33. 2
  34. 3
  35. 3
  36. 18
  37. 5
  38. 8
  39. 6
  40. 8

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