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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 869 · 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 49 and take away the sum of its digits. What do you get?
  2. 2.Take 51 and take away the sum of its digits. What do you get?
  3. 3.?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.5?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.113? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.185? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.32?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 50 and take away the sum of its digits. What do you get?
  9. 9.?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.61?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.13?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.297? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.3?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 33 and take away the sum of its digits. What do you get?
  15. 15.?254 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 60 and take away the sum of its digits. What do you get?
  17. 17.22?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.5?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.2?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 21 and take away the sum of its digits. What do you get?
  21. 21.769? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 74 and take away the sum of its digits. What do you get?
  23. 23.?597 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 13 and take away the sum of its digits. What do you get?
  25. 25.7?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 12 and take away the sum of its digits. What do you get?
  27. 27.504? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?897 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?645 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.321? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?084 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.6?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 78 and take away the sum of its digits. What do you get?
  34. 34.26? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.43?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 69 and take away the sum of its digits. What do you get?
  37. 37.?815 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.85?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 11 and take away the sum of its digits. What do you get?
  40. 40.Take 43 and take away the sum of its digits. What do you get?

Answer key

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

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