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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 907 · 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. 1.825? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.3?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 92 and take away the sum of its digits. What do you get?
  4. 4.?604 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.232? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?150 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.6?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?105 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?563 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.14?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 72 and take away the sum of its digits. What do you get?
  12. 12.Take 23 and take away the sum of its digits. What do you get?
  13. 13.Take 97 and take away the sum of its digits. What do you get?
  14. 14.8?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?641 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.62?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.106? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 80 and take away the sum of its digits. What do you get?
  19. 19.10?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 31 and take away the sum of its digits. What do you get?
  21. 21.?727 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?533 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 16 and take away the sum of its digits. What do you get?
  24. 24.Take 89 and take away the sum of its digits. What do you get?
  25. 25.?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.470? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.31?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 82 and take away the sum of its digits. What do you get?
  29. 29.?610 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?479 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.255? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 91 and take away the sum of its digits. What do you get?
  33. 33.63?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 67 and take away the sum of its digits. What do you get?
  36. 36.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 98 and take away the sum of its digits. What do you get?
  38. 38.Take 50 and take away the sum of its digits. What do you get?
  39. 39.?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?950 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 3
  2. 5
  3. 81
  4. 8
  5. 2
  6. 3
  7. 1
  8. 3
  9. 4
  10. 4
  11. 63
  12. 18
  13. 81
  14. 7
  15. 7
  16. 8
  17. 2
  18. 72
  19. 6
  20. 27
  21. 2
  22. 7
  23. 9
  24. 72
  25. 1
  26. 7
  27. 5
  28. 72
  29. 2
  30. 7
  31. 6
  32. 81
  33. 9
  34. 4
  35. 54
  36. 6
  37. 81
  38. 45
  39. 2
  40. 4

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