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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 427 · 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. 1.412? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 54 and take away the sum of its digits. What do you get?
  3. 3.Take 48 and take away the sum of its digits. What do you get?
  4. 4.77?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.7?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.6?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?024 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.26?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 67 and take away the sum of its digits. What do you get?
  10. 10.Take 20 and take away the sum of its digits. What do you get?
  11. 11.Take 17 and take away the sum of its digits. What do you get?
  12. 12.172? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.1?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 92 and take away the sum of its digits. What do you get?
  15. 15.Take 28 and take away the sum of its digits. What do you get?
  16. 16.?142 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 58 and take away the sum of its digits. What do you get?
  18. 18.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?624 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.2?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.32?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.75?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?335 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.17?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?669 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 96 and take away the sum of its digits. What do you get?
  28. 28.Take 83 and take away the sum of its digits. What do you get?
  29. 29.?753 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.19?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.8?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?914 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 81 and take away the sum of its digits. What do you get?
  34. 34.6?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?890 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.8?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.192? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.73?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?976 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.88?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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