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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 211 · 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.?779 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 32 and take away the sum of its digits. What do you get?
  3. 3.4?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 18 and take away the sum of its digits. What do you get?
  5. 5.Take 26 and take away the sum of its digits. What do you get?
  6. 6.60? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.2?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 75 and take away the sum of its digits. What do you get?
  9. 9.27?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.410? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.89?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?109 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.69?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?244 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.56?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 12 and take away the sum of its digits. What do you get?
  17. 17.?543 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?678 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.2?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.5?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.7?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 44 and take away the sum of its digits. What do you get?
  25. 25.8?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.94? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 42 and take away the sum of its digits. What do you get?
  29. 29.?647 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?700 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?019 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.636? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 15 and take away the sum of its digits. What do you get?
  34. 34.Take 85 and take away the sum of its digits. What do you get?
  35. 35.Take 50 and take away the sum of its digits. What do you get?
  36. 36.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.390? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?903 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.73?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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