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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 94 · 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.?951 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?915 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 86 and take away the sum of its digits. What do you get?
  5. 5.453? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 56 and take away the sum of its digits. What do you get?
  7. 7.Take 15 and take away the sum of its digits. What do you get?
  8. 8.?627 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.3?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.42?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 42 and take away the sum of its digits. What do you get?
  12. 12.Take 19 and take away the sum of its digits. What do you get?
  13. 13.Take 40 and take away the sum of its digits. What do you get?
  14. 14.?824 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 62 and take away the sum of its digits. What do you get?
  16. 16.Take 75 and take away the sum of its digits. What do you get?
  17. 17.10?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?617 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 83 and take away the sum of its digits. What do you get?
  20. 20.Take 63 and take away the sum of its digits. What do you get?
  21. 21.Take 82 and take away the sum of its digits. What do you get?
  22. 22.1?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.4?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 97 and take away the sum of its digits. What do you get?
  25. 25.Take 98 and take away the sum of its digits. What do you get?
  26. 26.Take 55 and take away the sum of its digits. What do you get?
  27. 27.?692 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.2?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.834? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 31 and take away the sum of its digits. What do you get?
  32. 32.1?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 24 and take away the sum of its digits. What do you get?
  34. 34.?075 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?049 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.52?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.210? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 50 and take away the sum of its digits. What do you get?
  40. 40.?010 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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