My watch has a forwards runnign stopwatch and a backwards running stopwiatch. I start the backwards one and let it go, and start and stop the forwards running one to time my Day 2 stuff. When I finish a round, I pull up the backwards count and subjtract 3 minutes from that and jot the tiem down on the wall so I know when to start again.
And then when I run, I have to recalculate how to swap back and forth between running and walking so that I do all the time that I'm supposed to.
And then, we're obsessed with distances ran, repititions completed, time expended, calories burned, and pounds lost. I'm just sayin, there sure seems to be a lot of math. :)