I'm going to give my even answers so far just to compare and see if everyone else is getting the same. Some are a little weird in my opinion. I used a calculator on a few too. -By the way, go here and make sure your preferences are set right so it makes these easier to read.
$ 38 = \pi $
$ 48 = x - \arctan{x} + c $
$ 50 = -22.578 $
$ 56 = \frac{\pi}{4} + \ln{2} $