Last updated: November 9, 2:30 p.m. EST

Joe Biden has been projected as the winner of the U.S. presidential election by several major news organizations. More than 145 million popular votes have been counted nationwide. Biden received more than 75 million of them.

But in the U.S., voters don’t directly elect the president. Instead, we use a system called the Electoral College. The candidate who receives the most popular votes in a state wins that state’s electoral votes. There are 538 electoral votes in all. The candidate who wins at least 270 of them is elected president.

Wins in 23 states and Washington, D.C., pushed Biden past the magic number of 270. (Click here to learn more about the Electoral College.)

The race between Biden and President Donald Trump was too close to call on Election Day. Hundreds of thousands of mail-in ballots still had to be counted. As election workers continued counting in several key states, Biden built up a big enough lead to be projected as the winner.

Trump, however, has not yet conceded the election. His campaign team has announced that it would insist on a recount of the votes in Wisconsin and Georgia. In those states, a candidate is allowed to ask for a recount in elections where the results are especially close.

Trump’s campaign has also filed lawsuits in several states. He believes that the vote count is incorrect. So far, there is no evidence to support this claim.

On Saturday night, Biden made a victory speech. “I will work as hard for those who didn’t vote for me as those who did,” he told the crowd in Wilmington, Delaware, and millions watching at home.

The victory will make history in more ways than one. At 77 years old, Biden is the oldest person ever elected president. Also, his vice president, Kamala Harris, will be the first woman to ever hold that office. The U.S. senator from California will also be the first Black woman and first Asian American elected to the second-highest position in government.

“While I may be the first woman in this office, I will not be the last,” Harris said during her speech in Wilmington. “Because every little girl watching tonight sees that this is a country of possibilities.”

On December 14, the Electoral College will make the election results official. If the current results hold up, Biden would become the nation’s 46th president after taking the oath of office in January.

Before then, Biden will work on setting his agenda for the next four years. The president-elect says his biggest goal is stopping the spread of Covid-19. He also says he wants to unite the country after a challenging election season.

“With full hearts and steady hands, with faith in America and in each other, with a love of country—and a thirst for justice—let us be the nation that we know we can be,” said Biden.