2. (2 points) Boy Vasya had two numbers written in his notebook. He decreased each of them by 1 and found that the product of the numbers remained the same. Find the sum of the original numbers.
Answer: 1.

## Solution:

Let the numbers be $x$ and $y$. We can set up the equation: $(x-1)(y-1)=x y$. Expanding the brackets and removing $x y$ from both sides, we get $-x-y+1=0$. Therefore, $x+y=1$.