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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 754 · 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. 1.14?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.11?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.358? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?487 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.8?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?706 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.8?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.360? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 17 and take away the sum of its digits. What do you get?
  11. 11.2?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.6?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 56 and take away the sum of its digits. What do you get?
  15. 15.1?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 43 and take away the sum of its digits. What do you get?
  17. 17.764? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.8?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?125 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.189? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?455 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.24? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 12 and take away the sum of its digits. What do you get?
  25. 25.1?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.101? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.7?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 83 and take away the sum of its digits. What do you get?
  29. 29.Take 63 and take away the sum of its digits. What do you get?
  30. 30.3?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.602? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 25 and take away the sum of its digits. What do you get?
  34. 34.Take 78 and take away the sum of its digits. What do you get?
  35. 35.6?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 22 and take away the sum of its digits. What do you get?
  37. 37.87?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 47 and take away the sum of its digits. What do you get?
  39. 39.?453 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.28?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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