The instructions are right there:. "Round each number to the nearest whole number.". DO that !
25.311 ===> 25
4.65 ===> 5
Your ESTIMATE is 25 x 5 .
You don't expect it to be exactly right, but you can do it quickly in your head. That estimate is 125.
When you take a sharp pencil and actually work out all the decimals, it's actually 117.69615 .
But 125 was plenty close enough for what you need to know right now, and you didn't even have to go get your calculator.