This is Bob. He lives in the wilderness and loves to climb mountains.

Bob might be just a Teddy Bear but he is very smart and likes to learn new things.

One day, Bob started to wonder if he could calculate the area under the mountains that he climbs every day.

This is when his friend Frank told him about something he had learned called Calculus.

Apparently calculus could help you calculate the area present under any curve. Bob was very impressed and wanted to learn how to do that as soon as possible.

See this curve looks just like a mountain and if you take the integral from point a to point b of the function of the curve, then you get the area under the curve from point a to point b!

Wait what? That was so confusing.

Don't worry, I'll explain it to you again.