You’re reading Significant Digits, a daily digest of the numbers tucked inside the news.

4 in 5 chance

The midterm elections are 15 days away. They are so close that if you bought some milk today, it would still be perfectly fine to drink by the time the new Congress was determined. Speaking of the new Congress: The Republicans’ chances of holding the Senate are themselves holding. Those chances sat at 4-in-5, or about 79 percent, as of Monday morning. The overall Senate map has been a bit boring. “Boring is good for Republicans; they seem to be holding the ground they gained during the Supreme Court confirmation hearings,” my colleague Nathaniel Rakich writes. [FiveThirtyEight]

18 deaths and more than 170 injuries

One of the fastest trains in Taiwan derailed on Sunday. The crash killed at least 18 people and injured more than 170 others. The train can travel up to 93 mph. After the crash, one car was tipped over at a 75-degree angle and its entire right side had been destroyed. There was no word yet on the cause. [Associated Press]

80 percent of the fossil’s pieces

Back in early September, the venerable National Museum of Brazil, in Rio de Janeiro, was nearly totally destroyed by a raging fire. But parts of its most prized possession, a human fossil called Luzia, have now been found in the ruins. Eighty percent of the pieces of Luzia, which was named after the 3.2 million-year-old remains of “Lucy,” have been recovered so far. Luzia was discovered in 1975 in Belo Horizonte, and at 12,000 years old it is the oldest human skeleton from the region. [The New York Times]

5,000 migrants

A caravan of Central American migrants in southern Mexico, who are fleeing poverty and violence and most of whom are bound for the U.S. border, grew to some 5,000 people over the weekend. President Trump called them “hardened criminals.” [NPR]

1.4 million Americans

The Trump administration’s Department of Health and Human Services is reportedly “spearheading an effort to establish a legal definition of sex” — a definition that would be either male or female, and would be unchangeable and determined by the genitals that a person was born with. The definition would, therefore, eliminate federal recognition of an estimated 1.4 million Americans who recognize themselves as a gender other than the one they were born into. [The New York Times]

$2.22 billion in prizes

Tomorrow’s Mega Millions jackpot stands at a possible $1.6 billion and Wednesday’s Powerball’s at $620 million, for a potential lotto bonanza of $2.22 billion this week. If you happened to win them both (and not pay taxes on them, because I don’t want to do the math) you’d become about the 1,103rd richest person in the world. [CNN]

CORRECTION (Oct. 22, 2018, 12:30 p.m.): A previous version of this article incorrectly said a deadly train crash happened in Thailand. It happened in Taiwan.

Love digits? Find even more in FiveThirtyEight’s new book of math and logic puzzles, “The Riddler.” It’s in stores now! I hope you dig it.

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