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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 662 · 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. 1.122? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.8?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?390 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 59 and take away the sum of its digits. What do you get?
  6. 6.Take 15 and take away the sum of its digits. What do you get?
  7. 7.2?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.8?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.8?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 55 and take away the sum of its digits. What do you get?
  12. 12.Take 97 and take away the sum of its digits. What do you get?
  13. 13.?010 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?577 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 66 and take away the sum of its digits. What do you get?
  18. 18.47?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.20?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?503 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 76 and take away the sum of its digits. What do you get?
  23. 23.?641 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.164? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 70 and take away the sum of its digits. What do you get?
  26. 26.1?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 65 and take away the sum of its digits. What do you get?
  28. 28.420? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.6?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?875 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 30 and take away the sum of its digits. What do you get?
  32. 32.11?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 83 and take away the sum of its digits. What do you get?
  34. 34.Take 27 and take away the sum of its digits. What do you get?
  35. 35.Take 89 and take away the sum of its digits. What do you get?
  36. 36.?781 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?356 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 71 and take away the sum of its digits. What do you get?
  39. 39.80?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?06 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. 5
  3. 6
  4. 6
  5. 45
  6. 9
  7. 5
  8. 4
  9. 3
  10. 3
  11. 45
  12. 81
  13. 8
  14. 8
  15. 2
  16. 8
  17. 54
  18. 8
  19. 7
  20. 1
  21. 1
  22. 63
  23. 7
  24. 7
  25. 63
  26. 9
  27. 54
  28. 3
  29. 4
  30. 7
  31. 27
  32. 3
  33. 72
  34. 18
  35. 72
  36. 2
  37. 4
  38. 63
  39. 6
  40. 3

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