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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 208 · 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.?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.230? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?496 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?230 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.5?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 86 and take away the sum of its digits. What do you get?
  7. 7.Take 57 and take away the sum of its digits. What do you get?
  8. 8.Take 53 and take away the sum of its digits. What do you get?
  9. 9.Take 21 and take away the sum of its digits. What do you get?
  10. 10.68?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.593? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.5?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 87 and take away the sum of its digits. What do you get?
  14. 14.?314 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.3?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.5?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 28 and take away the sum of its digits. What do you get?
  18. 18.Take 59 and take away the sum of its digits. What do you get?
  19. 19.?293 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.854? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 32 and take away the sum of its digits. What do you get?
  22. 22.Take 40 and take away the sum of its digits. What do you get?
  23. 23.62?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.684? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 25 and take away the sum of its digits. What do you get?
  27. 27.Take 64 and take away the sum of its digits. What do you get?
  28. 28.?623 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 12 and take away the sum of its digits. What do you get?
  30. 30.Take 30 and take away the sum of its digits. What do you get?
  31. 31.11?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.3?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 48 and take away the sum of its digits. What do you get?
  34. 34.Take 20 and take away the sum of its digits. What do you get?
  35. 35.?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.18?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.5?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 27 and take away the sum of its digits. What do you get?
  39. 39.?400 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.31?1 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. 4
  3. 8
  4. 4
  5. 5
  6. 72
  7. 45
  8. 45
  9. 18
  10. 6
  11. 1
  12. 4
  13. 72
  14. 1
  15. 5
  16. 7
  17. 18
  18. 45
  19. 4
  20. 1
  21. 27
  22. 36
  23. 2
  24. 1
  25. 9
  26. 18
  27. 54
  28. 7
  29. 9
  30. 27
  31. 9
  32. 7
  33. 36
  34. 18
  35. 2
  36. 1
  37. 8
  38. 18
  39. 5
  40. 4

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