4+(27-12•2)/2
the answer is 5.5 but can someone explain it

Yes sure ! We follow the order of operation ( PEMDAS ) :

4+(27-12•2)/2

4+(27 - 24 ) /2

4+ 3/2

8/2 + 3/2 = 11/2

Following the order of operation , we first start with the parenthes , inside the parenthesis we have multiplication and subtraction . We start with multiplication , and then we subtract ... and do same denominator ..

the square root of what number? if you add that, then someone will probably answer the question.