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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 921 · 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. 1.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.128? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.765? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.24?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 92 and take away the sum of its digits. What do you get?
  6. 6.718? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.20?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.2?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 82 and take away the sum of its digits. What do you get?
  10. 10.10?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.876? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?016 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.360? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.301? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.30?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 17 and take away the sum of its digits. What do you get?
  17. 17.46?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 52 and take away the sum of its digits. What do you get?
  19. 19.68?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 24 and take away the sum of its digits. What do you get?
  21. 21.77?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.89?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 38 and take away the sum of its digits. What do you get?
  25. 25.333? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 64 and take away the sum of its digits. What do you get?
  27. 27.?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 54 and take away the sum of its digits. What do you get?
  29. 29.8?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 37 and take away the sum of its digits. What do you get?
  31. 31.Take 25 and take away the sum of its digits. What do you get?
  32. 32.30? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 58 and take away the sum of its digits. What do you get?
  34. 34.55?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 48 and take away the sum of its digits. What do you get?
  36. 36.1?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.407? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.47? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?362 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.540? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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