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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 526 · 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 49 and take away the sum of its digits. What do you get?
  2. 2.37?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.41? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 50 and take away the sum of its digits. What do you get?
  6. 6.7?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?172 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.20?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.585? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.63?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.374? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?303 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 43 and take away the sum of its digits. What do you get?
  16. 16.?845 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?304 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 64 and take away the sum of its digits. What do you get?
  19. 19.Take 47 and take away the sum of its digits. What do you get?
  20. 20.Take 20 and take away the sum of its digits. What do you get?
  21. 21.Take 42 and take away the sum of its digits. What do you get?
  22. 22.?139 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.1?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.3?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.580? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.7?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.112? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 25 and take away the sum of its digits. What do you get?
  29. 29.1?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?736 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.268? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.831? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 71 and take away the sum of its digits. What do you get?
  35. 35.2?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.60?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.834? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.258? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 37 and take away the sum of its digits. What do you get?
  40. 40.259? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 36
  2. 8
  3. 6
  4. 4
  5. 45
  6. 7
  7. 8
  8. 8
  9. 4
  10. 9
  11. 8
  12. 4
  13. 3
  14. 3
  15. 36
  16. 1
  17. 2
  18. 54
  19. 36
  20. 18
  21. 36
  22. 5
  23. 1
  24. 5
  25. 5
  26. 6
  27. 5
  28. 18
  29. 3
  30. 2
  31. 2
  32. 5
  33. 6
  34. 63
  35. 1
  36. 8
  37. 3
  38. 3
  39. 27
  40. 2

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