1. Stating the problem: We need to perform the operation $$\begin{array}{r} 31587 \\ -42758 \\ +13796 \end{array}$$ where 31587 is the first number, minus 42758 is subtracted, and then plus 13796 is added. 2. First, subtract 42758 from 31587: $$31587 - 42758 = -11171$$ because 31587 is less than 42758. 3. Then add 13796 to the result: $$-11171 + 13796 = 2625$$ 4. Therefore, the final answer is: $$2625$$