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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 899 · 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. 1.1?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 94 and take away the sum of its digits. What do you get?
  3. 3.1?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?480 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?971 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?263 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.6?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?692 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.20?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.181? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.38?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.7?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.505? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.604? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?649 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?095 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.318? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 87 and take away the sum of its digits. What do you get?
  20. 20.30?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.697? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?200 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?561 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.853? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 33 and take away the sum of its digits. What do you get?
  27. 27.790? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.243? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 16 and take away the sum of its digits. What do you get?
  30. 30.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.55?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 46 and take away the sum of its digits. What do you get?
  33. 33.Take 70 and take away the sum of its digits. What do you get?
  34. 34.395? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?903 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 27 and take away the sum of its digits. What do you get?
  37. 37.Take 47 and take away the sum of its digits. What do you get?
  38. 38.3?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 88 and take away the sum of its digits. What do you get?
  40. 40.4?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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