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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 487 · 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 46 and take away the sum of its digits. What do you get?
  2. 2.?192 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.1?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 20 and take away the sum of its digits. What do you get?
  5. 5.120? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.899? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 38 and take away the sum of its digits. What do you get?
  8. 8.650? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 21 and take away the sum of its digits. What do you get?
  10. 10.504? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?220 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.810? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 56 and take away the sum of its digits. What do you get?
  14. 14.Take 40 and take away the sum of its digits. What do you get?
  15. 15.?795 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?914 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.16?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.350? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.5?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.251? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?412 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.1?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.276? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 49 and take away the sum of its digits. What do you get?
  26. 26.4?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.297? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 60 and take away the sum of its digits. What do you get?
  29. 29.Take 77 and take away the sum of its digits. What do you get?
  30. 30.663? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.26?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 26 and take away the sum of its digits. What do you get?
  33. 33.Take 18 and take away the sum of its digits. What do you get?
  34. 34.?116 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.4?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?499 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 11 and take away the sum of its digits. What do you get?
  38. 38.Take 47 and take away the sum of its digits. What do you get?
  39. 39.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.19?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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