We recently surpassed one billion math problems answered on Khan Academy. I've seen it coming for quite some time, and I still find it somewhat astounding.
Sure, all numbers on the Internet are big. That number simply reflects an unprecedented opportunity to now deliver education at scale.
When you give something away for free, people will often come in droves. But free math problems?
Sample exercise on Khan Academy
We hit a billion in just about two years, and the second billion will likely be much faster, as we routinely have 3-4 million problems answered every day.
The number is really just an early taste of how hungry the world is to learn. Despite everything you may have heard to the contrary, most people do find learning fun.
But it's only fun when it's on your own terms: When you are presented with material that is at your appropriate level; when you are given the opportunity to fail and succeed without judgment; when you feel like you are fully in control.
If math homework always felt like that, it wouldn't seem surprising that so many people are seeking free math problems.