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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 60 · 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.Take 44 and take away the sum of its digits. What do you get?
  2. 2.Take 30 and take away the sum of its digits. What do you get?
  3. 3.?361 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 48 and take away the sum of its digits. What do you get?
  5. 5.?155 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.84?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.47?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 58 and take away the sum of its digits. What do you get?
  10. 10.Take 83 and take away the sum of its digits. What do you get?
  11. 11.?631 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 55 and take away the sum of its digits. What do you get?
  13. 13.66?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 41 and take away the sum of its digits. What do you get?
  15. 15.52?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?400 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?667 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 14 and take away the sum of its digits. What do you get?
  19. 19.29?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.168? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 56 and take away the sum of its digits. What do you get?
  22. 22.Take 16 and take away the sum of its digits. What do you get?
  23. 23.837? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.4?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 89 and take away the sum of its digits. What do you get?
  26. 26.?262 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.111? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?517 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 63 and take away the sum of its digits. What do you get?
  31. 31.6?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.574? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 22 and take away the sum of its digits. What do you get?
  35. 35.30?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.17?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?325 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.216? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.1?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 51 and take away the sum of its digits. What do you get?

Answer key

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

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