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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 742 · 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. 1.39?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 59 and take away the sum of its digits. What do you get?
  3. 3.7?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.60?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 42 and take away the sum of its digits. What do you get?
  6. 6.621? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 25 and take away the sum of its digits. What do you get?
  8. 8.?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?528 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?492 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.760? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 48 and take away the sum of its digits. What do you get?
  13. 13.62?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.496? 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.?667 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.375? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?660 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.11?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.12?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 57 and take away the sum of its digits. What do you get?
  22. 22.Take 44 and take away the sum of its digits. What do you get?
  23. 23.729? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 31 and take away the sum of its digits. What do you get?
  25. 25.?302 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.72?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 37 and take away the sum of its digits. What do you get?
  28. 28.Take 77 and take away the sum of its digits. What do you get?
  29. 29.?817 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.8?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 51 and take away the sum of its digits. What do you get?
  32. 32.Take 47 and take away the sum of its digits. What do you get?
  33. 33.?664 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?516 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 49 and take away the sum of its digits. What do you get?
  36. 36.?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?489 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?808 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.4?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.6?4 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. 45
  3. 9
  4. 9
  5. 36
  6. 9
  7. 18
  8. 1
  9. 3
  10. 3
  11. 5
  12. 36
  13. 3
  14. 8
  15. 9
  16. 8
  17. 3
  18. 6
  19. 3
  20. 5
  21. 45
  22. 36
  23. 9
  24. 27
  25. 4
  26. 9
  27. 27
  28. 63
  29. 2
  30. 7
  31. 45
  32. 36
  33. 2
  34. 6
  35. 36
  36. 1
  37. 6
  38. 2
  39. 5
  40. 8

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