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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 598 · 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. 1.208? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.61?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.20?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?374 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.260? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.66?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 95 and take away the sum of its digits. What do you get?
  8. 8.Take 25 and take away the sum of its digits. What do you get?
  9. 9.Take 13 and take away the sum of its digits. What do you get?
  10. 10.363? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.83?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.379? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 72 and take away the sum of its digits. What do you get?
  14. 14.659? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.511? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.709? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.4?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?393 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?854 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.105? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?119 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 70 and take away the sum of its digits. What do you get?
  23. 23.Take 81 and take away the sum of its digits. What do you get?
  24. 24.Take 27 and take away the sum of its digits. What do you get?
  25. 25.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.746? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.1?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.5?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.631? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.343? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 42 and take away the sum of its digits. What do you get?
  32. 32.Take 28 and take away the sum of its digits. What do you get?
  33. 33.?093 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.66?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.1?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 94 and take away the sum of its digits. What do you get?
  37. 37.85?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.8?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.26?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 83 and take away the sum of its digits. What do you get?

Answer key

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

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