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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 607 · 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. 1.751? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.257? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.4?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?474 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 72 and take away the sum of its digits. What do you get?
  6. 6.Take 22 and take away the sum of its digits. What do you get?
  7. 7.707? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.84?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 12 and take away the sum of its digits. What do you get?
  10. 10.17?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.2?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.18?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.61?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.278? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.2?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.67?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.776? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.40? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.256? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.39?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.530? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?673 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 98 and take away the sum of its digits. What do you get?
  25. 25.368? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.135? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.286? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 35 and take away the sum of its digits. What do you get?
  29. 29.3?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.200? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.726? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.72? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?029 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.109? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.39? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?717 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 82 and take away the sum of its digits. What do you get?
  38. 38.53?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.2?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.153? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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