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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 502 · 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?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?007 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.6?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.2?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.451? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.3?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.8?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?136 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 35 and take away the sum of its digits. What do you get?
  11. 11.?739 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 72 and take away the sum of its digits. What do you get?
  13. 13.7?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 95 and take away the sum of its digits. What do you get?
  15. 15.689? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.484? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 21 and take away the sum of its digits. What do you get?
  18. 18.Take 59 and take away the sum of its digits. What do you get?
  19. 19.?557 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.6?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?179 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.187? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 13 and take away the sum of its digits. What do you get?
  24. 24.6?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.49?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?254 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 48 and take away the sum of its digits. What do you get?
  29. 29.39?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 14 and take away the sum of its digits. What do you get?
  31. 31.80?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 38 and take away the sum of its digits. What do you get?
  34. 34.?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?388 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?500 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?825 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.654? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.7?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 33 and take away the sum of its digits. What do you get?

Answer key

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

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