The open pit mine at Molycorp Minerals' rare earths mining and processing facility in Mountain Pass, Calif. The mine is expected to produce 40,000 tons of rare earth minerals each year after a $500 million expansion project. Courtesy of Molycorp Minerals hide caption

toggle caption Courtesy of Molycorp Minerals

In this April 2008 photo, Terry Crenshaw, warden's assistant at the Oklahoma State Penitentiary, walks past the gurney in the execution chamber in McAlester, Okla. Oklahoma is one of the few states that use pentobarbital in the lethal injection procedure. AP hide caption

toggle caption AP

Agents of Secret Stuff stars YouTube celebrity Ryan Higa as a spy operative who finds himself somewhat out of place when he's assigned to go undercover at a high school. Through YouTube, fans can find stars they can more easily relate to who may be ignored by Hollywood. YouTube hide caption

toggle caption YouTube

U.S. Marines attend a role call on the flight deck of the USS Essex, a multipurpose amphibious assault ship, in November. Defense Secretary Robert Gates says he wants to reduce the Marine Corps by 15,000 to 20,000 in the coming years. Ed Jones/Getty Images hide caption

toggle caption Ed Jones/Getty Images

During past State of the Union addresses, the aisle clearly divided the two parties — as in this photo from President Obama's address last year, in which Democrats are standing and Republicans sitting. Pablo Martinez Monsivais/AP hide caption

toggle caption Pablo Martinez Monsivais/AP

A baby cheetah, a little over a month old, gets its daily weigh-in. Bilal Qureshi/NPR hide caption

toggle caption Bilal Qureshi/NPR

Designer Roy Halston Frowick, known best by his middle name only, with model Pat Cleveland at a party following the Coty Awards in 1972. Halston frequently used Cleveland to showcase his fluid, body-hugging designs. Ron Galella/WireImage hide caption

toggle caption Ron Galella/WireImage

Who says monsters have to be scary? Some can be very helpful with your math homework. The monster above is actually showing you how to find the prime factors of the number 14. Click here to see Schwartz's illustrations of the numbers 1 to 100, factored. Richard Evan Schwartz hide caption

toggle caption Richard Evan Schwartz


Math Isn't So Scary With Help From These Monsters

A new children's book written and illustrated by a Brown University math professor makes complex ideas like prime and composite numbers easy (and fun) to understand.

Listen Loading… 4:37
  • Playlist
  • Download
  • Embed
    <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">

Fred Armisen and Carrie Brownstein in Portlandia. IFC hide caption

toggle caption IFC

The producers behind Gran Torino, starring Clint Eastwood (left) and Bee Vang, were lured to Michigan thanks to nearly $100 million in tax credits the state first offered in 2008. Anthony Michael Rivetti/Warner Bros. Pictures hide caption

toggle caption Anthony Michael Rivetti/Warner Bros. Pictures

A Red Flame grapefruit affected by the disease known as citrus greening, which leaves fruit sour, malformed and unusable -- and eventually kills the tree. Greg Allen/NPR hide caption

toggle caption Greg Allen/NPR
U.S. Customs & Border Protection

Mentor Carol Brooks, 72, wears a charm bracelet engraved with the names of the many refugees she’s helped in the past decade. "Some of them call me Mom," she says. Jennifer Ludden/NPR hide caption

toggle caption Jennifer Ludden/NPR

NPR thanks our sponsors

Become an NPR sponsor