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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 401 · 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. 1.8?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.492? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 97 and take away the sum of its digits. What do you get?
  5. 5.?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 96 and take away the sum of its digits. What do you get?
  7. 7.2?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.27? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 39 and take away the sum of its digits. What do you get?
  10. 10.2?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.44? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 23 and take away the sum of its digits. What do you get?
  13. 13.4?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.274? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.14?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.171? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.75?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 77 and take away the sum of its digits. What do you get?
  20. 20.?457 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.6?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?454 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.5?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?067 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 40 and take away the sum of its digits. What do you get?
  27. 27.Take 24 and take away the sum of its digits. What do you get?
  28. 28.Take 30 and take away the sum of its digits. What do you get?
  29. 29.429? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?627 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?467 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 68 and take away the sum of its digits. What do you get?
  33. 33.702? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 33 and take away the sum of its digits. What do you get?
  35. 35.29?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.27?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.550? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?075 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.6?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.40? 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. 3
  3. 1
  4. 81
  5. 8
  6. 81
  7. 1
  8. 9
  9. 27
  10. 4
  11. 1
  12. 18
  13. 6
  14. 9
  15. 5
  16. 9
  17. 9
  18. 6
  19. 63
  20. 2
  21. 3
  22. 5
  23. 9
  24. 1
  25. 5
  26. 36
  27. 18
  28. 27
  29. 3
  30. 3
  31. 1
  32. 54
  33. 9
  34. 27
  35. 7
  36. 3
  37. 8
  38. 6
  39. 5
  40. 5

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