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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 335 · 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 53 and take away the sum of its digits. What do you get?
  2. 2.76?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 57 and take away the sum of its digits. What do you get?
  4. 4.7?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.758? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 11 and take away the sum of its digits. What do you get?
  9. 9.Take 51 and take away the sum of its digits. What do you get?
  10. 10.25? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.50?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.3?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.4?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.890? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.2?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.40?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.447? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.848? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?642 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 91 and take away the sum of its digits. What do you get?
  22. 22.Take 88 and take away the sum of its digits. What do you get?
  23. 23.Take 44 and take away the sum of its digits. What do you get?
  24. 24.?033 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.2?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 94 and take away the sum of its digits. What do you get?
  27. 27.8?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.528? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 63 and take away the sum of its digits. What do you get?
  30. 30.Take 35 and take away the sum of its digits. What do you get?
  31. 31.2?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.6?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.62?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 67 and take away the sum of its digits. What do you get?
  36. 36.Take 76 and take away the sum of its digits. What do you get?
  37. 37.?349 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.223? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?737 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.2?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 45
  2. 2
  3. 45
  4. 4
  5. 7
  6. 9
  7. 1
  8. 9
  9. 45
  10. 2
  11. 1
  12. 1
  13. 5
  14. 1
  15. 8
  16. 3
  17. 3
  18. 3
  19. 7
  20. 6
  21. 81
  22. 72
  23. 36
  24. 3
  25. 8
  26. 81
  27. 2
  28. 3
  29. 54
  30. 27
  31. 5
  32. 6
  33. 6
  34. 1
  35. 54
  36. 63
  37. 2
  38. 2
  39. 1
  40. 6

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