18 birds are left then regroup a ten 28 I hope it’ helps

is already in simplest form.
But if you meant to say

, we would combine the first two terms.
Adding/subtracting like terms is the same as adding/subtracting whole numbers.

Therefore:

Which gives us:
Answer:
4/6
Step-by-step explanation:
1/2=3/6+1/6=4/6