How to access the calculator history on AOSP Android KitKat?
There is currently no way of accessing the history without a device that has a scrollwheel. For some reason, Google didn't implement any UI or touch screen functions with the history, and therefore the only way to access it is to scroll down with a scrollwheel. There's a bug report here.

There's an improved calculator app from CyanogenMod called CyanogenMod Calculator, which has a history. (The link should work but is untested since Google Play throws an SSL certificate error on my current connection)