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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 361 · 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. 1.605? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?044 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 73 and take away the sum of its digits. What do you get?
  4. 4.Take 51 and take away the sum of its digits. What do you get?
  5. 5.717? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.246? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.413? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?146 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?519 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?853 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?353 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.280? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 48 and take away the sum of its digits. What do you get?
  15. 15.Take 76 and take away the sum of its digits. What do you get?
  16. 16.Take 33 and take away the sum of its digits. What do you get?
  17. 17.3?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 64 and take away the sum of its digits. What do you get?
  19. 19.575? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 87 and take away the sum of its digits. What do you get?
  21. 21.Take 79 and take away the sum of its digits. What do you get?
  22. 22.20?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?006 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.663? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 35 and take away the sum of its digits. What do you get?
  27. 27.?609 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 90 and take away the sum of its digits. What do you get?
  29. 29.Take 92 and take away the sum of its digits. What do you get?
  30. 30.7?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?206 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 86 and take away the sum of its digits. What do you get?
  33. 33.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 13 and take away the sum of its digits. What do you get?
  36. 36.531? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?104 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 24 and take away the sum of its digits. What do you get?
  39. 39.241? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.493? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 7
  2. 1
  3. 63
  4. 45
  5. 3
  6. 6
  7. 1
  8. 1
  9. 7
  10. 3
  11. 2
  12. 7
  13. 8
  14. 36
  15. 63
  16. 27
  17. 5
  18. 54
  19. 1
  20. 72
  21. 63
  22. 8
  23. 3
  24. 1
  25. 3
  26. 27
  27. 3
  28. 81
  29. 81
  30. 5
  31. 1
  32. 72
  33. 1
  34. 3
  35. 9
  36. 9
  37. 4
  38. 18
  39. 2
  40. 2

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