Answer:
5 7/16
Explanation:
First off, make all the numbers have the same denominator.
In this case, the best one would be 16.
For 9 3/4, the four goes into 16 four times. So you multiply the 3 by four, and get 12 in the numerator. So it is now 9 12/16.
Next we have 3 1/8. 8 goes into 18 2 times. So you multiply 1 by 2 and get 2 in the numerator. So it is now 3 2/16.
Now, lets add the two together:
3 2/16+9 12/16 =
12 14/16
Now we know the sum of the two numbers.
Lets subtract this from 18 7/16:
18 7/16-12 14/16
=
5 7/16
This is your answer!
Hope this helps! :)