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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 924 · 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. 1.26?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.88?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?201 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?880 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?124 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 86 and take away the sum of its digits. What do you get?
  7. 7.138? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.8?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 56 and take away the sum of its digits. What do you get?
  10. 10.3?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?749 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.785? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.5?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.124? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 20 and take away the sum of its digits. What do you get?
  16. 16.Take 18 and take away the sum of its digits. What do you get?
  17. 17.284? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 99 and take away the sum of its digits. What do you get?
  19. 19.?556 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.802? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?377 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 96 and take away the sum of its digits. What do you get?
  23. 23.?149 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 63 and take away the sum of its digits. What do you get?
  25. 25.871? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?960 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.77?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 50 and take away the sum of its digits. What do you get?
  29. 29.2?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.6?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.22? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 78 and take away the sum of its digits. What do you get?
  33. 33.Take 27 and take away the sum of its digits. What do you get?
  34. 34.3?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 14 and take away the sum of its digits. What do you get?
  36. 36.192? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.6?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.340? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 90 and take away the sum of its digits. What do you get?
  40. 40.Take 57 and take away the sum of its digits. What do you get?

Answer key

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

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