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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 641 · 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 76 and take away the sum of its digits. What do you get?
  2. 2.Take 95 and take away the sum of its digits. What do you get?
  3. 3.4?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?066 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.3?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?749 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?113 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?161 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.87?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 14 and take away the sum of its digits. What do you get?
  12. 12.3?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.2?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.659? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?236 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.169? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?421 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 58 and take away the sum of its digits. What do you get?
  22. 22.200? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.716? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?028 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 62 and take away the sum of its digits. What do you get?
  26. 26.6?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 31 and take away the sum of its digits. What do you get?
  28. 28.?487 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 89 and take away the sum of its digits. What do you get?
  30. 30.215? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.62? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.87?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 70 and take away the sum of its digits. What do you get?
  35. 35.6?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?271 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.293? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.105? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 98 and take away the sum of its digits. What do you get?
  40. 40.?970 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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