Rounding error

I thought this was maybe getting a little obsessive when I turned right when I should have turned left so that I could add another mile to my return journey so that I could finish the month (for me at least - no more bike until June) with over 400 miles rather than the 300 that I'd planned.

Turns out my mental arithmetic is not what it should be and when I downloaded the data from my wee GPS, the total was only 399.51 miles. Argh. So I had to go back out and do at least another half a mile. A wee trip along to the boat would do it. And it did. 401.58.