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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 104 · 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.?755 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 58 and take away the sum of its digits. What do you get?
  3. 3.?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.44?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 21 and take away the sum of its digits. What do you get?
  6. 6.Take 25 and take away the sum of its digits. What do you get?
  7. 7.Take 81 and take away the sum of its digits. What do you get?
  8. 8.?664 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 68 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. 11.393? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.4?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 70 and take away the sum of its digits. What do you get?
  14. 14.87?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 84 and take away the sum of its digits. What do you get?
  16. 16.?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.6?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 54 and take away the sum of its digits. What do you get?
  19. 19.Take 15 and take away the sum of its digits. What do you get?
  20. 20.4?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.717? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?938 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.73?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 49 and take away the sum of its digits. What do you get?
  25. 25.567? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.591? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.330? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.84?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?618 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?539 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.7?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?715 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.7?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?898 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?251 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.585? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 60 and take away the sum of its digits. What do you get?
  38. 38.51?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.13?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 27 and take away the sum of its digits. What do you get?

Answer key

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

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