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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 954 · 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.?421 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 69 and take away the sum of its digits. What do you get?
  3. 3.Take 99 and take away the sum of its digits. What do you get?
  4. 4.Take 36 and take away the sum of its digits. What do you get?
  5. 5.199? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 52 and take away the sum of its digits. What do you get?
  7. 7.?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.741? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.32? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 82 and take away the sum of its digits. What do you get?
  12. 12.123? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.5?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.1?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.800? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?745 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?190 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 80 and take away the sum of its digits. What do you get?
  19. 19.Take 76 and take away the sum of its digits. What do you get?
  20. 20.49?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 31 and take away the sum of its digits. What do you get?
  22. 22.51?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?996 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.7?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?127 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 13 and take away the sum of its digits. What do you get?
  27. 27.?078 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.86?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.17?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 57 and take away the sum of its digits. What do you get?
  31. 31.Take 66 and take away the sum of its digits. What do you get?
  32. 32.?871 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 24 and take away the sum of its digits. What do you get?
  34. 34.3?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.7?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 74 and take away the sum of its digits. What do you get?
  37. 37.66?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.50?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.11?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 85 and take away the sum of its digits. What do you get?

Answer key

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

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