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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 363 · 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. 1.42?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 15 and take away the sum of its digits. What do you get?
  3. 3.?563 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?934 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?727 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.33? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?037 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.5?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?469 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 44 and take away the sum of its digits. What do you get?
  11. 11.5?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 46 and take away the sum of its digits. What do you get?
  13. 13.7?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.5?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?223 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.7?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 67 and take away the sum of its digits. What do you get?
  18. 18.Take 48 and take away the sum of its digits. What do you get?
  19. 19.?577 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.17?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 33 and take away the sum of its digits. What do you get?
  22. 22.558? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.54?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.2?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?915 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.75?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?089 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.774? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 53 and take away the sum of its digits. What do you get?
  32. 32.Take 13 and take away the sum of its digits. What do you get?
  33. 33.8?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.64?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?129 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?068 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.36?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.4?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.4?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 90 and take away the sum of its digits. What do you get?

Answer key

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

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