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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 599 · 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.?872 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?526 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?706 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 81 and take away the sum of its digits. What do you get?
  6. 6.Take 82 and take away the sum of its digits. What do you get?
  7. 7.?818 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?971 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?606 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?761 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.13?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?129 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?182 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 13 and take away the sum of its digits. What do you get?
  15. 15.561? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.13?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.6?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 31 and take away the sum of its digits. What do you get?
  20. 20.2?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 55 and take away the sum of its digits. What do you get?
  22. 22.1?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 27 and take away the sum of its digits. What do you get?
  24. 24.1?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.648? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?787 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 34 and take away the sum of its digits. What do you get?
  29. 29.?371 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 19 and take away the sum of its digits. What do you get?
  31. 31.?379 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.69?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.651? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.4?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.63? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?109 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 97 and take away the sum of its digits. What do you get?
  38. 38.?299 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 11 and take away the sum of its digits. What do you get?
  40. 40.294? 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. 5
  3. 5
  4. 5
  5. 72
  6. 72
  7. 1
  8. 1
  9. 6
  10. 4
  11. 9
  12. 6
  13. 7
  14. 9
  15. 6
  16. 4
  17. 1
  18. 5
  19. 27
  20. 5
  21. 45
  22. 8
  23. 18
  24. 4
  25. 9
  26. 4
  27. 5
  28. 27
  29. 7
  30. 9
  31. 8
  32. 4
  33. 6
  34. 6
  35. 9
  36. 8
  37. 81
  38. 7
  39. 9
  40. 3

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