You got to pay your taxes so I can give it to the poor.
We are all equal!
In a capitalist system, private citizens owned companies. Sometimes they used child labor for their business. This wasn't good for the children because they constantly got hurt and worked for long hours without a break.
It still has some capitalist principles but the government still have an active role when controlling the economy, they do this by redistributing wealth through programs like welfare, and free health care.
In a communist system, the government controls the businesses. The goal of this is a classless society and that everyone shares everything.