# Summation

What’s the sum of the first 100 counting numbers? Where does the sum of the powers of ½ converge to? How can you visualize the Taylor series expansion for sine?

Answer these questions (and more!) with summation in Desmos. Get started with the video on the right, then dive deeper with the resources and challenges below.

To use summation, you can find sigma in the Desmos keyboard (under FUNCTIONS and then misc) or by typing "sum":

If you populate the upper and lower bound, Desmos will output the summation answer.

You can also put a parameter for the upper and/or lower limits.