With the school year coming to a close, there's a growing concern about the state of America's education system.
Why Common Core tests are bad
Much of it centered around the nationwide standard known as the "Common Core" - a way to evaluate students, schools and teachers.
It started under the Bush administration, but now conservatives are one of its biggest opponents.
But one woman is making it part of her life's work to support the curriculum. In an interview with CNN's Erin Burnett, Melinda Gates explains why she backs Common Core.