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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 801 · 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 12 and take away the sum of its digits. What do you get?
  2. 2.30?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.870? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.4?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 53 and take away the sum of its digits. What do you get?
  6. 6.734? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 71 and take away the sum of its digits. What do you get?
  8. 8.1?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.8?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?709 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.53?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?130 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.60?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.18?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 56 and take away the sum of its digits. What do you get?
  19. 19.Take 78 and take away the sum of its digits. What do you get?
  20. 20.832? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 50 and take away the sum of its digits. What do you get?
  22. 22.?022 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 11 and take away the sum of its digits. What do you get?
  24. 24.Take 25 and take away the sum of its digits. What do you get?
  25. 25.3?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.1?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.7?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?304 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.8?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.487? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.119? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.347? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 32 and take away the sum of its digits. What do you get?
  35. 35.1?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?278 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?238 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 36 and take away the sum of its digits. What do you get?

Answer key

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

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