I'm by no means a mathematician so this may not be as interesting as some of our math/physics/engineering/compsci folks, but I definitely use basic algebra on the daily. I probably use fractions the most when I bake, especially when doubling or halving recipes. When I was a kid I used to try to figure out the amount of change owed before the cashier would tell my parents or calculate the number of coins before Mario Party would total it in some cases, and I still use some basic math of that sort. Mostly mental math though, I hardly ever break out the calculator even when it comes to tipping at restaurants.