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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 462 · 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.?285 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 76 and take away the sum of its digits. What do you get?
  3. 3.2?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 20 and take away the sum of its digits. What do you get?
  5. 5.561? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.75? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.6?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 71 and take away the sum of its digits. What do you get?
  9. 9.6?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.4?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.8?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 69 and take away the sum of its digits. What do you get?
  13. 13.?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?758 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 86 and take away the sum of its digits. What do you get?
  16. 16.?181 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.274? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.7?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 72 and take away the sum of its digits. What do you get?
  21. 21.6?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.290? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 19 and take away the sum of its digits. What do you get?
  25. 25.?762 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 75 and take away the sum of its digits. What do you get?
  27. 27.1?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 25 and take away the sum of its digits. What do you get?
  29. 29.Take 17 and take away the sum of its digits. What do you get?
  30. 30.7?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?175 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 22 and take away the sum of its digits. What do you get?
  34. 34.?635 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?692 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 78 and take away the sum of its digits. What do you get?
  37. 37.?673 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.72?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 73 and take away the sum of its digits. What do you get?
  40. 40.4?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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