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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 287 · 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. 1.369? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 68 and take away the sum of its digits. What do you get?
  3. 3.4?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?055 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 89 and take away the sum of its digits. What do you get?
  6. 6.Take 65 and take away the sum of its digits. What do you get?
  7. 7.?363 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?502 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 99 and take away the sum of its digits. What do you get?
  11. 11.Take 76 and take away the sum of its digits. What do you get?
  12. 12.544? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.39?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?979 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?717 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.856? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.206? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.86? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?863 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 81 and take away the sum of its digits. What do you get?
  23. 23.?715 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 60 and take away the sum of its digits. What do you get?
  26. 26.?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?538 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?977 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?535 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.36?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.1?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.4?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 48 and take away the sum of its digits. What do you get?
  34. 34.?947 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.619? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 94 and take away the sum of its digits. What do you get?
  37. 37.Take 71 and take away the sum of its digits. What do you get?
  38. 38.Take 64 and take away the sum of its digits. What do you get?
  39. 39.Take 45 and take away the sum of its digits. What do you get?
  40. 40.?562 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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