The Gates Foundation has learned that two questions can predict how much kids learn: 'Does your teacher use class time well?' and, 'When you're confused, does your teacher help you get straightened out?'

The concept of this so-called "TerraPower reactor" is that you, in the same reactor, you both burn and breed. So, instead of making plutonium and then extracting it, we take uranium - the 99.3 percent that you normally don't do anything with - we convert that, and we burn it.

I realized about 10 years ago that my wealth has to go back to society. A fortune, the size of which is hard to imagine, is best not passed on to one's children. It's not constructive for them.

Money has no utility to me beyond a certain point.

I've been very lucky, and therefore I owe it to try and reduce the inequity in the world. And that's kind of a religious belief. I mean, it's at least a moral belief.

Windows 8 is key to the future, the Surface computer.

I'm certainly well taken care of in terms of food and clothes ... Money has no utility to me beyond a certain point. Its utility is entirely in building an organization and getting the resources out to the poorest in the world.