99+12345+13

The answer is 83.73333333333333.

To solve this expression, we need to follow the order of operations, which is PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).

First, we need to perform any operations inside parentheses, but there are none in this expression.

Next, we need to evaluate any exponents, but there are none in this expression.

Then, we need to perform any multiplication and division, working from left to right.

9*9 = 81

123/45 = 2.7333333333333334

81 + 2.7333333333333334 = 83.73333333333333

Finally, we perform any addition and subtraction, working from left to right. In this case, there is only addition, so we are done.