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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 103 · 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. 1.73? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.3?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.6?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.237? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.2?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 67 and take away the sum of its digits. What do you get?
  8. 8.8?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?256 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 96 and take away the sum of its digits. What do you get?
  11. 11.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 42 and take away the sum of its digits. What do you get?
  13. 13.?597 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 82 and take away the sum of its digits. What do you get?
  15. 15.31?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.609? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.515? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.86?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 68 and take away the sum of its digits. What do you get?
  20. 20.246? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 34 and take away the sum of its digits. What do you get?
  22. 22.771? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.7?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 12 and take away the sum of its digits. What do you get?
  25. 25.1?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.3?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.532? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.240? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 39 and take away the sum of its digits. What do you get?
  30. 30.Take 32 and take away the sum of its digits. What do you get?
  31. 31.Take 62 and take away the sum of its digits. What do you get?
  32. 32.Take 78 and take away the sum of its digits. What do you get?
  33. 33.648? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.3?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 23 and take away the sum of its digits. What do you get?
  36. 36.Take 46 and take away the sum of its digits. What do you get?
  37. 37.3?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 52 and take away the sum of its digits. What do you get?
  39. 39.Take 87 and take away the sum of its digits. What do you get?
  40. 40.89?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 8
  2. 5
  3. 9
  4. 6
  5. 9
  6. 8
  7. 54
  8. 7
  9. 5
  10. 81
  11. 1
  12. 36
  13. 6
  14. 72
  15. 4
  16. 3
  17. 7
  18. 3
  19. 54
  20. 6
  21. 27
  22. 3
  23. 8
  24. 9
  25. 6
  26. 1
  27. 8
  28. 3
  29. 27
  30. 27
  31. 54
  32. 63
  33. 9
  34. 8
  35. 18
  36. 36
  37. 3
  38. 45
  39. 72
  40. 4

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