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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 231 · 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.Take 11 and take away the sum of its digits. What do you get?
  2. 2.4?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.37? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 61 and take away the sum of its digits. What do you get?
  5. 5.Take 16 and take away the sum of its digits. What do you get?
  6. 6.272? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?628 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 74 and take away the sum of its digits. What do you get?
  9. 9.2?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.2?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?363 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.481? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 94 and take away the sum of its digits. What do you get?
  14. 14.Take 33 and take away the sum of its digits. What do you get?
  15. 15.87?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.2?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.2?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.2?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 26 and take away the sum of its digits. What do you get?
  20. 20.Take 64 and take away the sum of its digits. What do you get?
  21. 21.?444 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 29 and take away the sum of its digits. What do you get?
  23. 23.Take 17 and take away the sum of its digits. What do you get?
  24. 24.?616 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 81 and take away the sum of its digits. What do you get?
  26. 26.Take 30 and take away the sum of its digits. What do you get?
  27. 27.60?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 43 and take away the sum of its digits. What do you get?
  29. 29.101? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.809? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?694 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 69 and take away the sum of its digits. What do you get?
  33. 33.?004 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.534? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?779 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 90 and take away the sum of its digits. What do you get?
  37. 37.Take 54 and take away the sum of its digits. What do you get?
  38. 38.?462 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.50?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.4?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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