Add −113+(−423).

To simplify the expression -113 + (-423), we need to add the two numbers together.

First, let's remove the parentheses by changing the signs of the negative numbers inside.
So, -113 + (-423) becomes -113 - 423.

Now, we can add the two numbers together:
-113 - 423 = -536.

Therefore, the sum of -113 + (-423) is -536.

−113+−423 equals -536.