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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 93 · 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?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 66 and take away the sum of its digits. What do you get?
  3. 3.Take 40 and take away the sum of its digits. What do you get?
  4. 4.458? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 18 and take away the sum of its digits. What do you get?
  6. 6.?164 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?980 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 60 and take away the sum of its digits. What do you get?
  9. 9.7?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 95 and take away the sum of its digits. What do you get?
  11. 11.?232 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 14 and take away the sum of its digits. What do you get?
  13. 13.603? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.2?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.8?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.7?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.6?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?510 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.73?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.7?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.5?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?430 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?190 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 64 and take away the sum of its digits. What do you get?
  27. 27.?024 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.37?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.808? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 11 and take away the sum of its digits. What do you get?
  31. 31.265? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?453 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.45?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.164? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?539 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?111 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.570? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 50 and take away the sum of its digits. What do you get?
  39. 39.581? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 47 and take away the sum of its digits. What do you get?

Answer key

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

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