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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 600 · 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. 1.2?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.2?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.80?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.806? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.239? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.505? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.3?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 66 and take away the sum of its digits. What do you get?
  10. 10.25?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.14?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.407? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 76 and take away the sum of its digits. What do you get?
  14. 14.Take 55 and take away the sum of its digits. What do you get?
  15. 15.Take 22 and take away the sum of its digits. What do you get?
  16. 16.3?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 42 and take away the sum of its digits. What do you get?
  18. 18.112? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 72 and take away the sum of its digits. What do you get?
  20. 20.Take 77 and take away the sum of its digits. What do you get?
  21. 21.501? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.77?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?997 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 32 and take away the sum of its digits. What do you get?
  25. 25.Take 61 and take away the sum of its digits. What do you get?
  26. 26.?723 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.34?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.90? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.366? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.8?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.4?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 91 and take away the sum of its digits. What do you get?
  34. 34.2?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.49?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?489 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.5?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.3?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 24 and take away the sum of its digits. What do you get?
  40. 40.?683 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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