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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 189 · 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. 1.379? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?273 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.23?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 53 and take away the sum of its digits. What do you get?
  5. 5.Take 91 and take away the sum of its digits. What do you get?
  6. 6.Take 43 and take away the sum of its digits. What do you get?
  7. 7.87?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.6?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 68 and take away the sum of its digits. What do you get?
  10. 10.Take 32 and take away the sum of its digits. What do you get?
  11. 11.?655 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?773 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.?703 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 79 and take away the sum of its digits. What do you get?
  16. 16.2?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.635? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.6?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 42 and take away the sum of its digits. What do you get?
  20. 20.Take 28 and take away the sum of its digits. What do you get?
  21. 21.3?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 50 and take away the sum of its digits. What do you get?
  23. 23.2?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?534 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 12 and take away the sum of its digits. What do you get?
  26. 26.1?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.1?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.21?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.59?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?013 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 75 and take away the sum of its digits. What do you get?
  32. 32.3?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 25 and take away the sum of its digits. What do you get?
  34. 34.?797 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 29 and take away the sum of its digits. What do you get?
  36. 36.526? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?610 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 31 and take away the sum of its digits. What do you get?
  39. 39.Take 83 and take away the sum of its digits. What do you get?
  40. 40.Take 47 and take away the sum of its digits. What do you get?

Answer key

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

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