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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 142 · 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. 1.461? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?826 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?782 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 86 and take away the sum of its digits. What do you get?
  5. 5.?572 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 26 and take away the sum of its digits. What do you get?
  8. 8.Take 24 and take away the sum of its digits. What do you get?
  9. 9.71?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.393? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?993 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.23?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?719 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.79?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 61 and take away the sum of its digits. What do you get?
  16. 16.?341 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 64 and take away the sum of its digits. What do you get?
  18. 18.46? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 92 and take away the sum of its digits. What do you get?
  21. 21.?515 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.345? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 41 and take away the sum of its digits. What do you get?
  24. 24.Take 71 and take away the sum of its digits. What do you get?
  25. 25.8?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.87?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.19?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.2?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?925 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.96? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 69 and take away the sum of its digits. What do you get?
  34. 34.?005 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.4?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?097 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.8?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 54 and take away the sum of its digits. What do you get?
  39. 39.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?38 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. 2
  3. 1
  4. 72
  5. 4
  6. 8
  7. 18
  8. 18
  9. 4
  10. 3
  11. 6
  12. 4
  13. 1
  14. 6
  15. 54
  16. 1
  17. 54
  18. 8
  19. 7
  20. 81
  21. 7
  22. 6
  23. 36
  24. 63
  25. 1
  26. 4
  27. 3
  28. 8
  29. 8
  30. 2
  31. 3
  32. 8
  33. 54
  34. 4
  35. 9
  36. 2
  37. 4
  38. 45
  39. 1
  40. 7

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