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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 771 · 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. 1.49? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 52 and take away the sum of its digits. What do you get?
  3. 3.1?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 54 and take away the sum of its digits. What do you get?
  5. 5.476? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 18 and take away the sum of its digits. What do you get?
  7. 7.Take 32 and take away the sum of its digits. What do you get?
  8. 8.624? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.58?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.29?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.5?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 31 and take away the sum of its digits. What do you get?
  13. 13.62?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.877? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.2?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.82?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.158? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.260? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 62 and take away the sum of its digits. What do you get?
  20. 20.53?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.5?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.510? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?661 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 47 and take away the sum of its digits. What do you get?
  25. 25.Take 19 and take away the sum of its digits. What do you get?
  26. 26.603? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?654 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.885? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.19?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 87 and take away the sum of its digits. What do you get?
  31. 31.Take 15 and take away the sum of its digits. What do you get?
  32. 32.Take 33 and take away the sum of its digits. What do you get?
  33. 33.383? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?438 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 51 and take away the sum of its digits. What do you get?
  36. 36.?548 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?916 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.45?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 50 and take away the sum of its digits. What do you get?
  40. 40.?931 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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