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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 808 · 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.Take 62 and take away the sum of its digits. What do you get?
  2. 2.8?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 81 and take away the sum of its digits. What do you get?
  4. 4.?746 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.127? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 46 and take away the sum of its digits. What do you get?
  7. 7.5?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.70?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?583 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 52 and take away the sum of its digits. What do you get?
  11. 11.29?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.364? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 80 and take away the sum of its digits. What do you get?
  14. 14.35?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.42?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 19 and take away the sum of its digits. What do you get?
  17. 17.3?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.50?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.103? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 14 and take away the sum of its digits. What do you get?
  23. 23.Take 38 and take away the sum of its digits. What do you get?
  24. 24.26?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?852 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.283? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?869 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?763 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.37? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 24 and take away the sum of its digits. What do you get?
  31. 31.52?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 41 and take away the sum of its digits. What do you get?
  33. 33.572? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.571? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 42 and take away the sum of its digits. What do you get?
  37. 37.Take 91 and take away the sum of its digits. What do you get?
  38. 38.401? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.86?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 66 and take away the sum of its digits. What do you get?

Answer key

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

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