First, it is easier to start by converting all these fractions to twelfths.
To do this we need to find out how many times 2 goes in to 12. That is 6.
So we multiply 6 by 1 to get 6, and 1/2 is now 6/12.
We do the same for 3/4: 4 goes into 12 3 times, and 3 times 3 is 9.
3/4 is now 9/12. Now we are able to add them all together.
Add the numerators, 9, 1 and 6, to get 16. This is 16/12.
Simplified, it is 1 4/12 or 1 1/3. Hope this helps!