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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 935 · 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.?202 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 13 and take away the sum of its digits. What do you get?
  3. 3.?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 35 and take away the sum of its digits. What do you get?
  5. 5.Take 21 and take away the sum of its digits. What do you get?
  6. 6.608? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.5?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?031 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 30 and take away the sum of its digits. What do you get?
  10. 10.Take 17 and take away the sum of its digits. What do you get?
  11. 11.Take 34 and take away the sum of its digits. What do you get?
  12. 12.Take 79 and take away the sum of its digits. What do you get?
  13. 13.Take 20 and take away the sum of its digits. What do you get?
  14. 14.Take 53 and take away the sum of its digits. What do you get?
  15. 15.6?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?091 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?137 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.15? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 12 and take away the sum of its digits. What do you get?
  21. 21.5?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 47 and take away the sum of its digits. What do you get?
  23. 23.Take 88 and take away the sum of its digits. What do you get?
  24. 24.151? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?780 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?588 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 81 and take away the sum of its digits. What do you get?
  28. 28.Take 78 and take away the sum of its digits. What do you get?
  29. 29.Take 77 and take away the sum of its digits. What do you get?
  30. 30.?408 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?732 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.89?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.278? 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.?775 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.221? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.385? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.6?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 94 and take away the sum of its digits. What do you get?
  40. 40.70?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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