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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 711 · 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 43 and take away the sum of its digits. What do you get?
  2. 2.Take 76 and take away the sum of its digits. What do you get?
  3. 3.5?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 98 and take away the sum of its digits. What do you get?
  5. 5.?249 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?223 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?993 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?758 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.2?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?128 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 36 and take away the sum of its digits. What do you get?
  12. 12.?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?255 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 47 and take away the sum of its digits. What do you get?
  15. 15.?179 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 88 and take away the sum of its digits. What do you get?
  17. 17.67? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.864? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?790 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 34 and take away the sum of its digits. What do you get?
  21. 21.Take 78 and take away the sum of its digits. What do you get?
  22. 22.?532 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?485 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. 25.248? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?580 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 49 and take away the sum of its digits. What do you get?
  28. 28.539? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 67 and take away the sum of its digits. What do you get?
  30. 30.232? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.83?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 18 and take away the sum of its digits. What do you get?
  33. 33.1?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.706? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?800 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 48 and take away the sum of its digits. What do you get?
  37. 37.4?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 41 and take away the sum of its digits. What do you get?
  40. 40.6?93 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. 63
  3. 4
  4. 81
  5. 3
  6. 2
  7. 6
  8. 7
  9. 7
  10. 7
  11. 27
  12. 8
  13. 6
  14. 36
  15. 1
  16. 72
  17. 5
  18. 9
  19. 2
  20. 27
  21. 63
  22. 8
  23. 1
  24. 81
  25. 4
  26. 5
  27. 36
  28. 1
  29. 54
  30. 2
  31. 8
  32. 9
  33. 5
  34. 5
  35. 1
  36. 36
  37. 9
  38. 5
  39. 36
  40. 9

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