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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 273 · 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.?082 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 37 and take away the sum of its digits. What do you get?
  3. 3.?021 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 75 and take away the sum of its digits. What do you get?
  5. 5.27?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.16?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 97 and take away the sum of its digits. What do you get?
  8. 8.460? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 86 and take away the sum of its digits. What do you get?
  10. 10.Take 88 and take away the sum of its digits. What do you get?
  11. 11.?560 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.3?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?779 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?570 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 31 and take away the sum of its digits. What do you get?
  16. 16.85?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?516 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.1?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 21 and take away the sum of its digits. What do you get?
  22. 22.5?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?435 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 27 and take away the sum of its digits. What do you get?
  26. 26.42?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 25 and take away the sum of its digits. What do you get?
  28. 28.736? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.4?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 69 and take away the sum of its digits. What do you get?
  31. 31.60?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.9?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 12 and take away the sum of its digits. What do you get?
  35. 35.Take 39 and take away the sum of its digits. What do you get?
  36. 36.247? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.662? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.813? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.509? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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