The sum[br][center] [math]\sum_{n=1}^{\infty}\frac{1}{4^n}=\frac{1}{4}+\frac{1}{16}+\frac{1}{64}+\frac{1}{256}+\cdots=\frac{1}{3}[/math] [/center]was [url=https://en.wikipedia.org/wiki/1/4_%2B_1/16_%2B_1/64_%2B_1/256_%2B_⋯]one of the first infinite series to be calculated[/url] in the history of mathematics. Archimedes calculated the sum circa 250 BC. [br][br]This activity helps you understand the calculation in a dynamic way.