system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does Germany have a chancellor and a president?
gpt
Most countries have a head of state and a head of government.  The head of government is usually called a Prime Minister, because a minister serves the head of state (president or monarch).  

So, in Canada, there is a Prime Minister who serves the Queen.  In France, there is a Prime Minister and a President, because there is no monarch.  And in Germany, where there is no monarch, there is a Chancellor and a President.  

Usually, when both of these roles exist, one of them is a figurehead - a symbolic role that has little real power, but may be of vital importance in line of succession, like the U.S. Vice Presidency.  That's true in the case of Germany, where the President has little real power while the Chancellor handles the day-to-day business of making laws and signing treaties.