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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 851 · 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.?916 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 70 and take away the sum of its digits. What do you get?
  3. 3.46?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?169 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.26?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 63 and take away the sum of its digits. What do you get?
  7. 7.81?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 53 and take away the sum of its digits. What do you get?
  9. 9.Take 43 and take away the sum of its digits. What do you get?
  10. 10.Take 44 and take away the sum of its digits. What do you get?
  11. 11.Take 18 and take away the sum of its digits. What do you get?
  12. 12.302? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.88? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 78 and take away the sum of its digits. What do you get?
  15. 15.?768 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 49 and take away the sum of its digits. What do you get?
  17. 17.Take 79 and take away the sum of its digits. What do you get?
  18. 18.3?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?732 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 37 and take away the sum of its digits. What do you get?
  21. 21.Take 16 and take away the sum of its digits. What do you get?
  22. 22.6?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.492? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.9?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 36 and take away the sum of its digits. What do you get?
  26. 26.14?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 76 and take away the sum of its digits. What do you get?
  28. 28.3?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.1?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?608 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?167 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 58 and take away the sum of its digits. What do you get?
  33. 33.8?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?917 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.1?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.22?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 45 and take away the sum of its digits. What do you get?
  38. 38.?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.3?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.300? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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