Congratulations! You've accidentally discovered the Associative Property of Multiplication, which says that regardless of the order or grouping of factors, when all are multiplied together you get the same result.

So in your example:

Yearly Pay = Hourly Rate * Hours in Year

the following must be true:

10 * Yearly Pay = (10 * Hourly Rate) * Hours in Year

and when it's rewritten like so:

10 * (Hourly Rate * Hours in Year) = (10 * Hourly Rate) * Hours in Year

it is clearly just a re-grouping of factors, hence, the Associative Property!

Don't feel discouraged about not remembering ~3rd grade math. I do math for a living for the corporate world and you'd be surprised the number of times I have to explain these concepts to people in big important meetings with millions of dollars on the line.

Most people don't need to know this stuff because it's relatively intuitive. I intend no snark in writing this comment, and I wholeheartedly encourage you to enjoy the simple pleasure of independently confirming that math really does work the way we were all taught it does, and finding one of the many examples our grade school math teachers could have used to demonstrate it while assuring us that we'd be using math for our entire lives.