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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 445 · 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. 1.2?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.11? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.571? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 33 and take away the sum of its digits. What do you get?
  5. 5.11?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 51 and take away the sum of its digits. What do you get?
  7. 7.?433 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 23 and take away the sum of its digits. What do you get?
  9. 9.44?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 59 and take away the sum of its digits. What do you get?
  11. 11.?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.24?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.20?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?506 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?516 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.6?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 22 and take away the sum of its digits. What do you get?
  18. 18.4?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.236? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.114? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.21?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?102 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.7?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 67 and take away the sum of its digits. What do you get?
  25. 25.Take 54 and take away the sum of its digits. What do you get?
  26. 26.44?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.56?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.31?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 75 and take away the sum of its digits. What do you get?
  30. 30.1?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?686 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.7?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.771? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.8?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.393? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?830 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 39 and take away the sum of its digits. What do you get?
  38. 38.?901 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 12 and take away the sum of its digits. What do you get?
  40. 40.?109 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. 7
  3. 5
  4. 27
  5. 8
  6. 45
  7. 8
  8. 18
  9. 5
  10. 45
  11. 3
  12. 1
  13. 7
  14. 7
  15. 6
  16. 4
  17. 18
  18. 4
  19. 7
  20. 3
  21. 6
  22. 6
  23. 1
  24. 54
  25. 45
  26. 6
  27. 8
  28. 4
  29. 63
  30. 3
  31. 7
  32. 2
  33. 3
  34. 9
  35. 3
  36. 7
  37. 27
  38. 8
  39. 9
  40. 8

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