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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 451 · 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. 1.85?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.264? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 66 and take away the sum of its digits. What do you get?
  4. 4.762? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 67 and take away the sum of its digits. What do you get?
  7. 7.Take 50 and take away the sum of its digits. What do you get?
  8. 8.716? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.218? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.6?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.60?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 99 and take away the sum of its digits. What do you get?
  13. 13.30?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.43?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.7?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.8?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.74?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 39 and take away the sum of its digits. What do you get?
  19. 19.?889 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.4?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.56?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.64? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.475? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?998 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 73 and take away the sum of its digits. What do you get?
  27. 27.8?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.718? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 46 and take away the sum of its digits. What do you get?
  30. 30.52?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 60 and take away the sum of its digits. What do you get?
  32. 32.20?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.1?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.5?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.77?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 43 and take away the sum of its digits. What do you get?
  37. 37.85?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?599 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 88 and take away the sum of its digits. What do you get?
  40. 40.22?9 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. 6
  3. 54
  4. 3
  5. 1
  6. 54
  7. 45
  8. 4
  9. 7
  10. 9
  11. 1
  12. 81
  13. 8
  14. 2
  15. 7
  16. 1
  17. 4
  18. 27
  19. 2
  20. 9
  21. 5
  22. 8
  23. 9
  24. 2
  25. 1
  26. 63
  27. 9
  28. 2
  29. 36
  30. 3
  31. 54
  32. 3
  33. 7
  34. 2
  35. 2
  36. 36
  37. 1
  38. 4
  39. 72
  40. 5

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