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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 978 · 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 34 and take away the sum of its digits. What do you get?
  2. 2.Take 32 and take away the sum of its digits. What do you get?
  3. 3.Take 18 and take away the sum of its digits. What do you get?
  4. 4.3?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 31 and take away the sum of its digits. What do you get?
  6. 6.5?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 66 and take away the sum of its digits. What do you get?
  8. 8.?932 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.83?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.44?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.56?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.886? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.61?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 23 and take away the sum of its digits. What do you get?
  15. 15.39?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.1?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.62?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 49 and take away the sum of its digits. What do you get?
  19. 19.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 37 and take away the sum of its digits. What do you get?
  21. 21.Take 33 and take away the sum of its digits. What do you get?
  22. 22.5?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.603? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 76 and take away the sum of its digits. What do you get?
  25. 25.Take 36 and take away the sum of its digits. What do you get?
  26. 26.198? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.50?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?872 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.205? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?453 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 28 and take away the sum of its digits. What do you get?
  32. 32.Take 56 and take away the sum of its digits. What do you get?
  33. 33.53?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 22 and take away the sum of its digits. What do you get?
  35. 35.Take 48 and take away the sum of its digits. What do you get?
  36. 36.?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 45 and take away the sum of its digits. What do you get?
  38. 38.80?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?214 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 53 and take away the sum of its digits. What do you get?

Answer key

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

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