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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 925 · 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.?998 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?673 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?599 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 15 and take away the sum of its digits. What do you get?
  5. 5.1?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.8?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 24 and take away the sum of its digits. What do you get?
  8. 8.Take 16 and take away the sum of its digits. What do you get?
  9. 9.340? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 35 and take away the sum of its digits. What do you get?
  11. 11.Take 36 and take away the sum of its digits. What do you get?
  12. 12.Take 37 and take away the sum of its digits. What do you get?
  13. 13.?584 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.74? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 95 and take away the sum of its digits. What do you get?
  16. 16.Take 84 and take away the sum of its digits. What do you get?
  17. 17.499? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 26 and take away the sum of its digits. What do you get?
  19. 19.?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.651? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.23?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 72 and take away the sum of its digits. What do you get?
  23. 23.7?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 52 and take away the sum of its digits. What do you get?
  25. 25.?671 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 75 and take away the sum of its digits. What do you get?
  27. 27.Take 51 and take away the sum of its digits. What do you get?
  28. 28.?246 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 11 and take away the sum of its digits. What do you get?
  30. 30.2?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.755? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.8?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 99 and take away the sum of its digits. What do you get?
  34. 34.Take 43 and take away the sum of its digits. What do you get?
  35. 35.Take 30 and take away the sum of its digits. What do you get?
  36. 36.57?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.1?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?908 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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