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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 622 · 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.?353 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 78 and take away the sum of its digits. What do you get?
  3. 3.796? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 47 and take away the sum of its digits. What do you get?
  5. 5.?328 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.7?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.40?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.652? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?593 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.737? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.46?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.64?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 57 and take away the sum of its digits. What do you get?
  16. 16.Take 70 and take away the sum of its digits. What do you get?
  17. 17.Take 72 and take away the sum of its digits. What do you get?
  18. 18.Take 53 and take away the sum of its digits. What do you get?
  19. 19.2?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 75 and take away the sum of its digits. What do you get?
  21. 21.?788 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?753 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 36 and take away the sum of its digits. What do you get?
  24. 24.107? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 96 and take away the sum of its digits. What do you get?
  26. 26.2?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.395? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.102? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 39 and take away the sum of its digits. What do you get?
  31. 31.?635 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.227? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 69 and take away the sum of its digits. What do you get?
  34. 34.76?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?327 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 12 and take away the sum of its digits. What do you get?
  37. 37.?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 18 and take away the sum of its digits. What do you get?
  39. 39.8?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.5?61 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. 63
  3. 5
  4. 36
  5. 5
  6. 8
  7. 4
  8. 5
  9. 1
  10. 9
  11. 1
  12. 9
  13. 2
  14. 3
  15. 45
  16. 63
  17. 63
  18. 45
  19. 3
  20. 63
  21. 4
  22. 3
  23. 27
  24. 1
  25. 81
  26. 1
  27. 1
  28. 8
  29. 6
  30. 27
  31. 4
  32. 7
  33. 54
  34. 5
  35. 6
  36. 9
  37. 6
  38. 9
  39. 4
  40. 6

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