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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 74 · 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 82 and take away the sum of its digits. What do you get?
  2. 2.Take 73 and take away the sum of its digits. What do you get?
  3. 3.?331 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.8?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.50?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.1?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 49 and take away the sum of its digits. What do you get?
  8. 8.4?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?646 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 76 and take away the sum of its digits. What do you get?
  11. 11.?992 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?172 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 61 and take away the sum of its digits. What do you get?
  15. 15.Take 45 and take away the sum of its digits. What do you get?
  16. 16.1?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 80 and take away the sum of its digits. What do you get?
  18. 18.Take 27 and take away the sum of its digits. What do you get?
  19. 19.522? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.8?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.5?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 92 and take away the sum of its digits. What do you get?
  23. 23.74?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?902 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 90 and take away the sum of its digits. What do you get?
  27. 27.47?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 78 and take away the sum of its digits. What do you get?
  29. 29.63?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 26 and take away the sum of its digits. What do you get?
  31. 31.2?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.364? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 89 and take away the sum of its digits. What do you get?
  34. 34.Take 63 and take away the sum of its digits. What do you get?
  35. 35.469? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.8?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.134? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.4?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?906 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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