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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 953 · 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. 1.66?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 43 and take away the sum of its digits. What do you get?
  3. 3.Take 18 and take away the sum of its digits. What do you get?
  4. 4.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?458 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.81?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.36?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?285 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?772 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.3?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 68 and take away the sum of its digits. What do you get?
  13. 13.405? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?551 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.44?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 36 and take away the sum of its digits. What do you get?
  17. 17.848? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.3?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?347 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 86 and take away the sum of its digits. What do you get?
  21. 21.899? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.23?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.836? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.594? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.4?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 80 and take away the sum of its digits. What do you get?
  27. 27.218? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 73 and take away the sum of its digits. What do you get?
  29. 29.?743 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 37 and take away the sum of its digits. What do you get?
  31. 31.Take 97 and take away the sum of its digits. What do you get?
  32. 32.?694 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.78?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.3?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?934 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 74 and take away the sum of its digits. What do you get?
  38. 38.280? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.71?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.55?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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