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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 481 · 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. 1.864? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 11 and take away the sum of its digits. What do you get?
  3. 3.?795 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 74 and take away the sum of its digits. What do you get?
  5. 5.Take 37 and take away the sum of its digits. What do you get?
  6. 6.?067 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 14 and take away the sum of its digits. What do you get?
  8. 8.5?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 90 and take away the sum of its digits. What do you get?
  10. 10.723? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.4?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.86?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 87 and take away the sum of its digits. What do you get?
  14. 14.?104 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.44?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.24?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 42 and take away the sum of its digits. What do you get?
  18. 18.?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.453? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 89 and take away the sum of its digits. What do you get?
  21. 21.Take 16 and take away the sum of its digits. What do you get?
  22. 22.6?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?480 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 93 and take away the sum of its digits. What do you get?
  25. 25.?475 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.73?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.3?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.547? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?997 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?961 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.7?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?152 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.99? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.480? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 84 and take away the sum of its digits. What do you get?
  38. 38.Take 47 and take away the sum of its digits. What do you get?
  39. 39.2?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.4?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 9
  2. 9
  3. 6
  4. 63
  5. 27
  6. 5
  7. 9
  8. 7
  9. 81
  10. 6
  11. 1
  12. 8
  13. 72
  14. 4
  15. 4
  16. 8
  17. 36
  18. 4
  19. 6
  20. 72
  21. 9
  22. 2
  23. 6
  24. 81
  25. 2
  26. 8
  27. 4
  28. 2
  29. 2
  30. 2
  31. 2
  32. 2
  33. 1
  34. 9
  35. 9
  36. 6
  37. 72
  38. 36
  39. 3
  40. 3

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