Most adults, let alone most 17-year-olds, tend to get a little nervous when it’s time to give a speech in front of their peers. But on Tuesday, student activist and Nobel Peace Prize winner Malala Yousafzai confidently addressed an audience filled with some of the world’s most influential power brokers—prime ministers, a crown prince, and the secretary-general of the United Nations—and issued a clear challenge: Commit to free, high-quality, universal K–12 education for the world’s children, and cut back on military spending to pay for it.

Yousafzai issued the directive to attendees at the Oslo Summit on Education for Development, a two-day gathering held to discuss progress toward the United Nation’s Millennium Development Goals around education.

So, Why Should You Care? One of the U.N.’s education goals was that by 2015, every boy and girl around the world would be enrolled in primary school, which is usually kindergarten through eighth grade. According to the United Nations, 50 million more children and 40 million more teenagers are in school today than before efforts to meet the Millennium Development Goals were announced in 2000. But owing to factors such as poverty and war, 58 million kids—10 percent of the world’s children—still don’t attend primary school.

UNESCO’s Education for All Global Monitoring Report puts the cost of educating every child on the planet through grade 12 at $340 billion. The expense of extending education opportunities from grades 9–12 is $39 billion of that amount.

“It may appear as a huge number, but the reality is that it is not at all,” Yousafzai told summit attendees. “The world spends many times more than this on weapons and military. In fact and unfortunately, $39 billion are spent on militaries only just in eight days.”

As Yousafzai points out in the video above, the U.N.’s current goal is inadequate because it doesn’t include high school, something the world leaders at the Oslo summit wouldn’t tolerate for their own kids. “Only nine years of education is not enough. If nine years is not enough for your children, then it is not enough for the rest of the world’s children,” she told the audience. Around 63 million teenagers around the planet never go to high school, according to the U.N.

“World leaders need to be serious and think of the world as one country, as the land of all people, where every person deserves equality, equal rights, no matter whether they are black or white, man or woman, rich or poor,” she said. “A child should not be kept away from the opportunity of going to school or receiving health care just because that child is from a poor family or is from a poor country. That child has no choice. World leaders need to think of the rest of the world’s children as their own children.”

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Yousafzai, who is the focus of the upcoming documentary He Named Me Malala, survived a 2012 assassination attempt by a Taliban gunman in her native Pakistan when she was 14. She was targeted because she spoke up about girls’ unequal access to schooling in the South Asian nation. Since then, she has become a global advocate for universal education, particularly for girls.

In her speech, Yousafzai also asked everyday people to join her in putting pressure on world leaders to invest in education instead of defense spending. The activist turns 18 on July 12, and in lieu of sending her presents, she hopes people will post photos of themselves with their favorite books on social media with the hashtag #BooksNotBullets. “Books are a better investment in our future than bullets. Books, not bullets, will pave the path toward peace and prosperity,” she said.