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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 369 · 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 27 and take away the sum of its digits. What do you get?
  2. 2.317? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 32 and take away the sum of its digits. What do you get?
  4. 4.?940 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 13 and take away the sum of its digits. What do you get?
  6. 6.11?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 68 and take away the sum of its digits. What do you get?
  8. 8.68?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.786? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?253 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 52 and take away the sum of its digits. What do you get?
  12. 12.79?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?398 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 60 and take away the sum of its digits. What do you get?
  15. 15.Take 37 and take away the sum of its digits. What do you get?
  16. 16.6?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.64?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.8?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.130? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.71?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 20 and take away the sum of its digits. What do you get?
  24. 24.2?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.5?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?206 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 62 and take away the sum of its digits. What do you get?
  30. 30.1?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.189? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 98 and take away the sum of its digits. What do you get?
  34. 34.?173 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.41? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.5?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 11 and take away the sum of its digits. What do you get?
  39. 39.8?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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