To solve this problem, you must follow the order of operations (parentheses, exponents, multiplication and division from left to right, and addition and subtraction from left to right):

First, do multiplication and division:
468 x 269 = 125892
125892 ÷ 2 = 62946

Then, do the addition and subtraction:
12349 + 13578 = 25927

Now, divide the sum by the result of the multiplication and division:
25927 ÷ 62946 = 0.411699

Therefore, the final answer is 0.411699.