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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 258 · 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. 1.82?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.5?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.562? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.146? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.52?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?940 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 32 and take away the sum of its digits. What do you get?
  9. 9.5?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 54 and take away the sum of its digits. What do you get?
  11. 11.Take 23 and take away the sum of its digits. What do you get?
  12. 12.?310 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 49 and take away the sum of its digits. What do you get?
  14. 14.30?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 29 and take away the sum of its digits. What do you get?
  16. 16.?008 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 36 and take away the sum of its digits. What do you get?
  18. 18.?687 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.31? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?988 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.7?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 71 and take away the sum of its digits. What do you get?
  26. 26.Take 66 and take away the sum of its digits. What do you get?
  27. 27.Take 97 and take away the sum of its digits. What do you get?
  28. 28.4?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.6?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.46?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.1?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 14 and take away the sum of its digits. What do you get?
  34. 34.?400 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 27 and take away the sum of its digits. What do you get?
  36. 36.36?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 33 and take away the sum of its digits. What do you get?
  38. 38.?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.652? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?248 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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