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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 113 · 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.?164 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.145? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?092 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.4?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 22 and take away the sum of its digits. What do you get?
  6. 6.Take 12 and take away the sum of its digits. What do you get?
  7. 7.Take 29 and take away the sum of its digits. What do you get?
  8. 8.?971 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?481 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.4?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.2?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 91 and take away the sum of its digits. What do you get?
  14. 14.6?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.330? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?437 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 41 and take away the sum of its digits. What do you get?
  18. 18.Take 35 and take away the sum of its digits. What do you get?
  19. 19.291? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 60 and take away the sum of its digits. What do you get?
  21. 21.?310 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?200 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.361? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.4?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 68 and take away the sum of its digits. What do you get?
  27. 27.824? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?583 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?305 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?096 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.664? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?788 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 44 and take away the sum of its digits. What do you get?
  34. 34.2?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.869? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.8?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.83?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.8?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.39?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.31?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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