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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 799 · 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.Take 75 and take away the sum of its digits. What do you get?
  2. 2.?188 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.283? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?205 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?517 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.3?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 95 and take away the sum of its digits. What do you get?
  8. 8.?728 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 25 and take away the sum of its digits. What do you get?
  10. 10.367? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.4?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.67?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.84?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.3?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.8?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?508 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?879 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 60 and take away the sum of its digits. What do you get?
  20. 20.26?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 48 and take away the sum of its digits. What do you get?
  22. 22.204? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?588 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 15 and take away the sum of its digits. What do you get?
  26. 26.5?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.27?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?895 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.4?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?013 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 92 and take away the sum of its digits. What do you get?
  32. 32.Take 81 and take away the sum of its digits. What do you get?
  33. 33.?601 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 39 and take away the sum of its digits. What do you get?
  35. 35.?197 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?750 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.623? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.60?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?262 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.347? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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