Did you know that, if you ever want to work out how many seconds there are in a year without using a calculator, just tell whichever nub is asking you that (look it up, sheesh!) that it's "pi"*10^{7}? Pi as in 3.14159265358979323...

This is bizarrely a seriously good approximation, giving you an answer of 31,415,927 seconds when the "real" answer is closer to 31,557,000 seconds. But it's a very good approximation and even has the advantage of possible cancelling out with any other pi you may have in the sum.