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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 218 · 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 72 and take away the sum of its digits. What do you get?
  2. 2.?415 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 61 and take away the sum of its digits. What do you get?
  4. 4.4?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 31 and take away the sum of its digits. What do you get?
  6. 6.Take 44 and take away the sum of its digits. What do you get?
  7. 7.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.2?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.500? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 54 and take away the sum of its digits. What do you get?
  11. 11.305? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.63?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 48 and take away the sum of its digits. What do you get?
  14. 14.764? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.282? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 37 and take away the sum of its digits. What do you get?
  17. 17.Take 46 and take away the sum of its digits. What do you get?
  18. 18.15?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.1?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.18? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.742? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.84?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 65 and take away the sum of its digits. What do you get?
  24. 24.Take 75 and take away the sum of its digits. What do you get?
  25. 25.2?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?955 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?939 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.Take 62 and take away the sum of its digits. What do you get?
  30. 30.7?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 38 and take away the sum of its digits. What do you get?
  32. 32.Take 79 and take away the sum of its digits. What do you get?
  33. 33.2?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.24?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.3?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 25 and take away the sum of its digits. What do you get?
  37. 37.?943 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.4?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 69 and take away the sum of its digits. What do you get?
  40. 40.?390 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. 8
  3. 54
  4. 9
  5. 27
  6. 36
  7. 9
  8. 9
  9. 4
  10. 45
  11. 1
  12. 4
  13. 36
  14. 1
  15. 6
  16. 27
  17. 36
  18. 2
  19. 5
  20. 9
  21. 5
  22. 2
  23. 54
  24. 63
  25. 6
  26. 8
  27. 6
  28. 72
  29. 54
  30. 3
  31. 27
  32. 63
  33. 2
  34. 9
  35. 3
  36. 18
  37. 2
  38. 1
  39. 54
  40. 6

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