If the 61-year-old Microsoft co-founder and billionaire Bill Gates could whisper in the ear of his 19-year-old-self, he would have a few things to say about what he's learned.

In an expansive and far-reaching reddit Ask Me Anything session on Monday, Gates reveals the three best pieces of advice he would give his younger self.

Intelligence is multifaceted

"I would explain that smartness is not single-dimensional and not quite as important as I thought it was back then," Gates says.

While he now realizes that IQ may be overrated, Gates has often emphasized the importance of being curious. An interest in the world can and should be fostered, he says.

"I think having parents and teachers reinforce your curiosity and explain what they are fascinated with makes a big difference," Gates says.