Has anyone knows how to create Math Formula in Medium?(Help)

I am student from South Korea. I study statistics and sometimes post on my medium. Because there is no medium support, I write in math editor and screen capture it. Two drawbacks in these methods.

1. When I found out mistake, it is difficult to fix, because it is an “image”
2. The size of image is random, because I screen-capture it. Especially in Mobile….

I saw some well-organized medium posting such as

The Y Combinator (no, not that one)

Can You Solve This Intro Probability Problem?

Brett Berry, Ev Williams, Medium, Ayaka Nonaka all anyone knows about this? Please Help!