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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 632 · 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. 1.15?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.80?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?051 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.289? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 73 and take away the sum of its digits. What do you get?
  6. 6.Take 32 and take away the sum of its digits. What do you get?
  7. 7.3?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?050 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 44 and take away the sum of its digits. What do you get?
  10. 10.?007 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.5?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?599 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 24 and take away the sum of its digits. What do you get?
  15. 15.Take 56 and take away the sum of its digits. What do you get?
  16. 16.725? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 25 and take away the sum of its digits. What do you get?
  19. 19.1?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 47 and take away the sum of its digits. What do you get?
  21. 21.Take 52 and take away the sum of its digits. What do you get?
  22. 22.1?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.72?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.66?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 50 and take away the sum of its digits. What do you get?
  26. 26.Take 66 and take away the sum of its digits. What do you get?
  27. 27.2?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?627 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 29 and take away the sum of its digits. What do you get?
  30. 30.Take 40 and take away the sum of its digits. What do you get?
  31. 31.?679 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 98 and take away the sum of its digits. What do you get?
  33. 33.373? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.72?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 26 and take away the sum of its digits. What do you get?
  36. 36.14?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.214? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.4?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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