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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 403 · 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.?130 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.13?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.67?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.5?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 66 and take away the sum of its digits. What do you get?
  6. 6.Take 70 and take away the sum of its digits. What do you get?
  7. 7.421? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 58 and take away the sum of its digits. What do you get?
  9. 9.?538 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.359? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 81 and take away the sum of its digits. What do you get?
  12. 12.Take 35 and take away the sum of its digits. What do you get?
  13. 13.Take 84 and take away the sum of its digits. What do you get?
  14. 14.2?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 77 and take away the sum of its digits. What do you get?
  16. 16.?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.24?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.5?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.25?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.8?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?226 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 26 and take away the sum of its digits. What do you get?
  23. 23.Take 63 and take away the sum of its digits. What do you get?
  24. 24.Take 12 and take away the sum of its digits. What do you get?
  25. 25.20?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 36 and take away the sum of its digits. What do you get?
  27. 27.Take 27 and take away the sum of its digits. What do you get?
  28. 28.1?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 33 and take away the sum of its digits. What do you get?
  30. 30.Take 15 and take away the sum of its digits. What do you get?
  31. 31.817? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?698 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?143 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.686? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.336? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?896 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 17 and take away the sum of its digits. What do you get?
  38. 38.Take 44 and take away the sum of its digits. What do you get?
  39. 39.37?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 43 and take away the sum of its digits. What do you get?

Answer key

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

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