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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 963 · 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 36 and take away the sum of its digits. What do you get?
  2. 2.703? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?061 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.261? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 80 and take away the sum of its digits. What do you get?
  6. 6.3?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.620? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.7?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 29 and take away the sum of its digits. What do you get?
  10. 10.Take 42 and take away the sum of its digits. What do you get?
  11. 11.?920 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 43 and take away the sum of its digits. What do you get?
  13. 13.?833 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 62 and take away the sum of its digits. What do you get?
  15. 15.Take 71 and take away the sum of its digits. What do you get?
  16. 16.?777 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.35?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.1?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.173? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.794? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?970 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.33?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 76 and take away the sum of its digits. What do you get?
  25. 25.?679 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.1?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?983 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 13 and take away the sum of its digits. What do you get?
  30. 30.Take 69 and take away the sum of its digits. What do you get?
  31. 31.389? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 32 and take away the sum of its digits. What do you get?
  33. 33.Take 48 and take away the sum of its digits. What do you get?
  34. 34.4?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.560? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 20 and take away the sum of its digits. What do you get?
  37. 37.759? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 21 and take away the sum of its digits. What do you get?
  39. 39.Take 22 and take away the sum of its digits. What do you get?
  40. 40.?938 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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