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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 947 · 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.?389 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.5?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.74?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 36 and take away the sum of its digits. What do you get?
  5. 5.Take 47 and take away the sum of its digits. What do you get?
  6. 6.Take 56 and take away the sum of its digits. What do you get?
  7. 7.6?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.65?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.32?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?664 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.86?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.7?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?008 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 13 and take away the sum of its digits. What do you get?
  16. 16.508? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 99 and take away the sum of its digits. What do you get?
  18. 18.7?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 39 and take away the sum of its digits. What do you get?
  20. 20.2?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 69 and take away the sum of its digits. What do you get?
  22. 22.?760 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 72 and take away the sum of its digits. What do you get?
  24. 24.53?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.20?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?557 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.1?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 45 and take away the sum of its digits. What do you get?
  29. 29.?370 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 67 and take away the sum of its digits. What do you get?
  31. 31.7?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.160? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.6?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 44 and take away the sum of its digits. What do you get?
  38. 38.3?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 59 and take away the sum of its digits. What do you get?
  40. 40.6?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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