WASHINGTON — United States citizens over the age of 18 can choose to vote in presidential elections. This is called the popular vote.

But American voters don’t actually pick the president through a majority vote. That’s the job of the electoral college. In 2016, a candidate will need at least 270 electoral votes to become president.

This system is strange to many, but it goes back to the earliest days of the founding of the United States of America. The founding fathers created the electoral college because they worried states with smaller populations might not be fairly represented.

They also didn’t think the “common man” was informed enough to choose a suitable president. So they created the electoral college, which is a group of selectors who cast votes as representatives of each state.

Today, it has 538 members. That’s one for every member of the House of Representatives and Senate, representing all 50 states. In addition, Washington DC has three electoral college members.

To win the presidency, a candidate must win at least 270 electoral votes.

Winning electoral votes is mostly achieved by winning the popular vote in each state. Win California’s popular vote and you take home the state’s 55 electoral votes. Win the popular vote in Texas and you are awarded that state’s 38 electoral votes.

This is called a winner-take-all system.

But sometimes, a candidate wins the popular vote nationally but doesn’t amass enough electoral votes. This happened in 2000 when Democratic candidate Al Gore won the popular vote nationwide, but Republican George W. Bush won Florida in a close contest.

Bush’s win in Florida was enough to give him the electoral vote victory, and the presidency, despite Gore beating Bush by roughly half a million popular votes.

Usually the electoral college and the popular vote produce the same winner. Only four times in America’s history has the popular vote been different from the electoral vote.