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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 344 · 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 66 and take away the sum of its digits. What do you get?
  2. 2.7?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.5?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?795 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?740 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.1?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 72 and take away the sum of its digits. What do you get?
  8. 8.Take 81 and take away the sum of its digits. What do you get?
  9. 9.Take 54 and take away the sum of its digits. What do you get?
  10. 10.Take 24 and take away the sum of its digits. What do you get?
  11. 11.?997 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.60? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.3?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.7?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?286 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.15?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.25?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?998 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?533 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.135? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?867 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.1?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?726 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 98 and take away the sum of its digits. What do you get?
  26. 26.Take 22 and take away the sum of its digits. What do you get?
  27. 27.Take 77 and take away the sum of its digits. What do you get?
  28. 28.Take 18 and take away the sum of its digits. What do you get?
  29. 29.?034 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.87? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.1?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.691? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 19 and take away the sum of its digits. What do you get?
  34. 34.313? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 86 and take away the sum of its digits. What do you get?
  36. 36.?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?505 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?407 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 13 and take away the sum of its digits. What do you get?
  40. 40.Take 82 and take away the sum of its digits. What do you get?

Answer key

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

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