What's the first musical instrument? Then Josie sings a song explaining it's the human voice.

Using mean to get the expected value in a discrete random distribution.

Bill provides a brief background on the history of measurement and explains why humans developed standard units of measurement. He explains how the meter was developed and talks about the simplicity of the metric system.

Bad man tests the children on their ability to find circumference.

We meet number two, and he shows us all the things that two can do.