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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 842 · 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 54 and take away the sum of its digits. What do you get?
  2. 2.Take 24 and take away the sum of its digits. What do you get?
  3. 3.?528 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.20?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.4?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 28 and take away the sum of its digits. What do you get?
  7. 7.Take 61 and take away the sum of its digits. What do you get?
  8. 8.Take 27 and take away the sum of its digits. What do you get?
  9. 9.2?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 92 and take away the sum of its digits. What do you get?
  11. 11.Take 86 and take away the sum of its digits. What do you get?
  12. 12.233? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.60?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.40?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?793 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 94 and take away the sum of its digits. What do you get?
  17. 17.7?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.39?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 87 and take away the sum of its digits. What do you get?
  20. 20.6?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 41 and take away the sum of its digits. What do you get?
  22. 22.?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 58 and take away the sum of its digits. What do you get?
  24. 24.Take 43 and take away the sum of its digits. What do you get?
  25. 25.?921 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.6?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.1?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.269? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?424 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.17?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 88 and take away the sum of its digits. What do you get?
  32. 32.Take 34 and take away the sum of its digits. What do you get?
  33. 33.41?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 23 and take away the sum of its digits. What do you get?
  35. 35.600? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.12? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.3?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.3?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.7?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?769 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. 18
  3. 3
  4. 9
  5. 7
  6. 18
  7. 54
  8. 18
  9. 9
  10. 81
  11. 72
  12. 1
  13. 6
  14. 5
  15. 8
  16. 81
  17. 8
  18. 2
  19. 72
  20. 4
  21. 36
  22. 1
  23. 45
  24. 36
  25. 6
  26. 5
  27. 2
  28. 1
  29. 8
  30. 4
  31. 72
  32. 27
  33. 8
  34. 18
  35. 3
  36. 6
  37. 3
  38. 6
  39. 5
  40. 5

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