Bill Gates has one piece of advice for future entrepreneurs

One thing Bill Gates is known to be good at is spotting opportunity.

His vision of the emerging opportunities in the world of computers spurred him to drop out of Harvard, Gates said Tuesday in a discussion of his and Melinda Gates' annual letter.

The pair talked with Lin-Manuel Miranda at Hunter College on Tuesday, and explained that the opportunity to directly improve a huge number of lives determined the Gates Foundation's focus on education and global health.

So it's worth listening to the advice Gates gave in response to a question about what future entrepreneurs should learn about.

Gates' answer: Go into science.

"The more you can learn the science, the more you will see where the opportunity is," he said.

Specifically, Gates thinks people should look at areas of the world where significant innovation is going to be needed in the near future to help humanity deal with coming challenges.

"If your talents take you toward science or programming, advances in biology or energy breakthroughs, those kinds of deep areas are going to be the biggest source of change," he said.

Gates said the challenges that he considers most important include global disease and the need to develop a new energy system for the planet. The answers to those problems will come from scientific research.

Personally, Gates said, he was lucky that software engineering grabbed his interest. He hired people to do the required marketing and sales, but it was his interest that allowed him to see the opportunity in the first place.

"If you have an inkling that science grabs you ... that's where a lot of the opportunity comes from," he said.