I have thoroughly enjoyed MNN blogger Shea Gunther's recent posts on converting kilometers to miles. I'm a runner, so I'm always trying to figure out how far that 10K run really is (in miles) or just how many 10Ks I need to run to train for a marathon (26.2 miles.)

Shea's first post, Cool math trick: Converting between miles and kilometers, gave me a quick and easy way to do these conversions in my head — something I have never been able to accomplish before. It also reminded me just how much math I have forgotten since my school years. Fibonacci? The golden spiral? I must have been absent that day — or maybe even that whole semester. With two kids in school, I started to wonder just how long I could hold on to my status as at-home tutor — particularly in the math department.

Coincidentally, I got an email the other day about a new book that helps parents brush up on their math skills. "Math for Grownups: Relearn the Arithmetic You Forgot From School," by Laura Laing takes readers through lots of "real-life" math scenarios such as comparing the fuel efficiency of two different cars, converting a recipe that feeds four into one that feeds eight, or figuring out if a product on sale at the store is really a "deal."

Granted, "Math For Grownups" doesn't go beyond elementary school mathematics, and it certainly doesn't touch Shea's Fibonacci series. Laing does offer up the standard miles-to-kilometers-to-miles conversion formulas, but she doesn't have any of Shea's cool conversion tricks. But the book does offer a great refresher in arithmetic as well as some tips for doing everyday math in your head.

By the way, what I loved even more than Shea's post was how fired up everyone got about it — about math! Some folks were downright belligerent in the comments, while others passionately offered up their own conversion tricks, leading to Shea's follow-up post: More ways to convert between miles and kilometers.

So now, thanks to Shea, even though my runs are slow, my math is not. But hey, I'm also a sailor. Shea, do you have any cool tricks for converting knots to miles?

'Math for grownups': Tips we can all use
Did MNN blogger Shea Gunther's recent math posts remind you of how much you've forgotten since school? This new book can help you brush up on your skills.