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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 952 · 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. 1.6?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.1?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.44?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.241? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 19 and take away the sum of its digits. What do you get?
  6. 6.Take 41 and take away the sum of its digits. What do you get?
  7. 7.Take 12 and take away the sum of its digits. What do you get?
  8. 8.6?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.210? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?433 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.1?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 18 and take away the sum of its digits. What do you get?
  13. 13.86? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.25?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 45 and take away the sum of its digits. What do you get?
  16. 16.?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?880 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.480? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.5?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.1?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.370? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.8?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.107? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.3?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.456? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.4?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?926 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 93 and take away the sum of its digits. What do you get?
  32. 32.589? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 61 and take away the sum of its digits. What do you get?
  34. 34.Take 77 and take away the sum of its digits. What do you get?
  35. 35.Take 21 and take away the sum of its digits. What do you get?
  36. 36.42?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 16 and take away the sum of its digits. What do you get?
  38. 38.?098 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.3?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.6?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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