When the common multiplier is greater than 1, for example y = 20(2)^x, then the exponential function will be increasing.  We call that exponential growth. 

Exponential Growth

When the common multiplier is between 0 and 1, like y = 100(.5)^x, then the function will be decreasing.  We call that exponential decay.

Exponential Decay

For even more review, you can watch a video about exponential growth by clicking here.