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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 752 · 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.?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 16 and take away the sum of its digits. What do you get?
  3. 3.23?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 85 and take away the sum of its digits. What do you get?
  5. 5.8?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?202 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?575 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 35 and take away the sum of its digits. What do you get?
  9. 9.Take 90 and take away the sum of its digits. What do you get?
  10. 10.587? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?753 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?115 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?946 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 99 and take away the sum of its digits. What do you get?
  16. 16.8?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.478? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 60 and take away the sum of its digits. What do you get?
  19. 19.1?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.2?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 62 and take away the sum of its digits. What do you get?
  22. 22.Take 42 and take away the sum of its digits. What do you get?
  23. 23.Take 87 and take away the sum of its digits. What do you get?
  24. 24.8?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.89?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 19 and take away the sum of its digits. What do you get?
  27. 27.1?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.8?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.3?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.70? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.9?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.1?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 47 and take away the sum of its digits. What do you get?
  34. 34.66?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.226? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 72 and take away the sum of its digits. What do you get?
  37. 37.186? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.190? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.85?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 75 and take away the sum of its digits. What do you get?

Answer key

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

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