Good work!

"Median" is simply the number that separates the top half of a group from the bottom half. It's different from "average," which is calculated by dividing the sum.
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For instance, take the wealth of 3 people, as follows:

Geoff Bozo's wealth = $130 million
Bozo the clown's wealth = $1 million
maJes.ty's wealth = $10,000

The AVERAGE wealth of those 3 people is .... $43.67 million. (The 3 amounts added together, then divided by 3). That would make maJes.ty appear filthy rich.

The MEDIAN wealth of those 3 people is ... $1 million. That would make maJes.ty very happy, but not filthy rich.
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Hope that helps you to understand.