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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 184 · 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. 1.1?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.72?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.252? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?205 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.1?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.20? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 29 and take away the sum of its digits. What do you get?
  8. 8.Take 91 and take away the sum of its digits. What do you get?
  9. 9.67?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 67 and take away the sum of its digits. What do you get?
  11. 11.Take 66 and take away the sum of its digits. What do you get?
  12. 12.?408 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.3?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 28 and take away the sum of its digits. What do you get?
  15. 15.?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 27 and take away the sum of its digits. What do you get?
  17. 17.Take 83 and take away the sum of its digits. What do you get?
  18. 18.7?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?159 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 37 and take away the sum of its digits. What do you get?
  21. 21.?482 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 33 and take away the sum of its digits. What do you get?
  23. 23.Take 58 and take away the sum of its digits. What do you get?
  24. 24.?185 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.9?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.135? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.8?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?445 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.7?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.3?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.1?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 23 and take away the sum of its digits. What do you get?
  33. 33.?559 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.389? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.853? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 42 and take away the sum of its digits. What do you get?
  37. 37.5?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.7?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 61 and take away the sum of its digits. What do you get?
  40. 40.Take 79 and take away the sum of its digits. What do you get?

Answer key

  1. 5
  2. 4
  3. 9
  4. 2
  5. 4
  6. 7
  7. 18
  8. 81
  9. 2
  10. 54
  11. 54
  12. 6
  13. 1
  14. 18
  15. 7
  16. 18
  17. 72
  18. 8
  19. 3
  20. 27
  21. 4
  22. 27
  23. 45
  24. 4
  25. 5
  26. 9
  27. 1
  28. 5
  29. 5
  30. 6
  31. 8
  32. 18
  33. 8
  34. 7
  35. 2
  36. 36
  37. 6
  38. 2
  39. 54
  40. 63

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