Quizlet raises $20 million for virtual flash cards

If you’re in high school in the United States, there’s at least a 50% chance you’re using Quizlet. And there’s an even better chance you’re at least familiar with it.

But for the rest of the adult population, times have changed since we were students. Educational apps like Quizlet help you do your homework and prepare for tests.

Quizlet builds modern-day flash cards and the startup says it uses machine learning to help figure out what students need the most help with. They have ready-built sets or people can customize their own, with the capability of adding charts, maps and images. (Check out our video review here.)

And with 30 million users, investors are betting that Quizlet will make good use of $20 million in additional funding. The startup raised a round led by Icon Ventures, with participation from Union Square Ventures, Costanoa Ventures and others. The San Francisco-based startup previously raised about $12 million.

Matthew Glotzbach, Quizlet’s CEO said that he plans to use the funding to expand internationally. Quizlet already has a global audience, but he wants to hire people in Western Europe and Asia.

“Whatever you’re trying to study, chances are you can find it on Quizlet,” said Glotzbach. “We can literally observe what works and what doesn’t from the billions of data points.”

He also says that not only students but “teachers like it because it really helps their students make efficient use of their study time.” They “can see where they are getting stuck.”

Quizlet has a freemium model. Quizlet Plus costs $19.99 per year custom voice recordings and long-term learning programs. They also have Quizlet Go, which has ad-free studying for just $1.99 per year.

Other apps in the homework help category include Photomath and Socrates.