This example demonstrates how using floats vs double and different precisions can impact simple calculations.
Please refer to page 24 of "Coincidences, Chaos, and All That Math Jazz" by Edward Burger and Michael Starbird
http://www.amazon.com/Coincidences-Chaos-That-Math-Jazz/dp/0393059456/ref=ed_oe_h
The difference between the float and double is noticeable in the first iteration. The difference between the two doubles will take more iterations.
Line 1, double, d = (d*d) -2
Line 2, float, f = (f*f) -2
Line 3, double, d = (((d*d) -2)*100.0)/100.0)