Whats the value of this expression?

30+[ (6:3) + (3+4) ]

To do this do the work in the brackets first. There are two parentheses. First solve 6/3. This gives you two. Now you add it to 7 (3+4) to get 9. Now you want to add 30 by 9. The answer is 39.

Solve the ones inside the parenthesis.

6:3 = 2

4+3=7 add 7 and 2 which is 9

now since everything inside the brackets and parenthesis is solved add the 30 to 9

30+9 = 39