The king of Mars & the startup that blew through $100 million

"The internet is the best school ever created."

I only spent first and second grade in Bulgaria. By second grade, I was failing math. 

I loved reading the word problems but stopped short of solving them. My mom tried. My dad tried. My teacher tried. The neighbor tried. A nerves-of-steel tutor tried. Nothing worked.

They’d be like, “OK, Polina, so Train A travels 70 miles per hour heading east, and Trai…