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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 674 · 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. 1.139? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.7?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.817? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.35?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.100? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 85 and take away the sum of its digits. What do you get?
  7. 7.?601 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 19 and take away the sum of its digits. What do you get?
  9. 9.?079 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 58 and take away the sum of its digits. What do you get?
  11. 11.8?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 83 and take away the sum of its digits. What do you get?
  13. 13.1?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 50 and take away the sum of its digits. What do you get?
  15. 15.326? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?139 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.52?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.529? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.78?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 26 and take away the sum of its digits. What do you get?
  21. 21.?451 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.29?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.4?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 98 and take away the sum of its digits. What do you get?
  25. 25.Take 69 and take away the sum of its digits. What do you get?
  26. 26.?376 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?538 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 32 and take away the sum of its digits. What do you get?
  29. 29.?539 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?726 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.242? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.6?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.489? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?506 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.8?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?044 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.36? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.11?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 49 and take away the sum of its digits. What do you get?
  40. 40.55?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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