Compare the expression 8×3+4 and 8×(3+4)

This is a lesson in order of operations...

PEMDAS- parentheses, exponents, multiplication, division, addition, and subtraction... That is the order in which you have to proceed during any math problem..

Your question gives an excellent example of why.

8x3+4=
in this question, we would do multiplication then addition for the answer...

24 + 4 = 28

Now the other one

8 x (3+4)  =
in this expression, we would do what is inside the parentheses first, the addition.  Then we would multiply...

8x 7 = 56

You see we have the same numbers and we are performing the same operations, but the difference is in the order that we perform them.  As you can see it does make a difference because we get a different result.

28 vs 56