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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 740 · 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. 1.523? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 52 and take away the sum of its digits. What do you get?
  4. 4.8?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 59 and take away the sum of its digits. What do you get?
  6. 6.Take 77 and take away the sum of its digits. What do you get?
  7. 7.60?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.11?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 85 and take away the sum of its digits. What do you get?
  10. 10.?485 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?919 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?290 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.24?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 18 and take away the sum of its digits. What do you get?
  15. 15.1?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.80?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?659 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 91 and take away the sum of its digits. What do you get?
  19. 19.19?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 69 and take away the sum of its digits. What do you get?
  21. 21.?020 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.202? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.23?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.718? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.462? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.99? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 11 and take away the sum of its digits. What do you get?
  30. 30.Take 46 and take away the sum of its digits. What do you get?
  31. 31.314? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.601? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.1?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?249 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?050 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 41 and take away the sum of its digits. What do you get?
  38. 38.1?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.12?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?447 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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