Best Free Multi-Function Calculator

I recently downloaded this Free Multi-Function Calculator on my computer.  I really only needed it for just a few simple calculations.  Later, my daughter asked for a four-function calculator, so I let her borrow this one.  We both agreed that it is easy to use.  The design is simple yet effective.  It is convenient to have it on my computer for when I need it.   I would definitely recommend this multi-function calculator.