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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 876 · 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.?557 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.6?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 50 and take away the sum of its digits. What do you get?
  4. 4.Take 84 and take away the sum of its digits. What do you get?
  5. 5.Take 34 and take away the sum of its digits. What do you get?
  6. 6.?203 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 65 and take away the sum of its digits. What do you get?
  8. 8.?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.36?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?303 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.47?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.5?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?803 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.3?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.6?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 57 and take away the sum of its digits. What do you get?
  17. 17.Take 90 and take away the sum of its digits. What do you get?
  18. 18.Take 44 and take away the sum of its digits. What do you get?
  19. 19.Take 66 and take away the sum of its digits. What do you get?
  20. 20.Take 69 and take away the sum of its digits. What do you get?
  21. 21.54?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?260 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?505 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.26?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?345 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 83 and take away the sum of its digits. What do you get?
  27. 27.?829 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.605? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.346? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.9?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.282? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?854 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 97 and take away the sum of its digits. What do you get?
  34. 34.?204 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.1?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 31 and take away the sum of its digits. What do you get?
  38. 38.6?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.4?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.178? 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. 6
  3. 45
  4. 72
  5. 27
  6. 4
  7. 54
  8. 4
  9. 8
  10. 3
  11. 3
  12. 3
  13. 7
  14. 4
  15. 6
  16. 45
  17. 81
  18. 36
  19. 54
  20. 54
  21. 2
  22. 1
  23. 8
  24. 3
  25. 6
  26. 72
  27. 8
  28. 7
  29. 5
  30. 2
  31. 6
  32. 1
  33. 81
  34. 3
  35. 5
  36. 3
  37. 27
  38. 9
  39. 1
  40. 2

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