If you want a gentler introduction, I recommend the first module of Andrew Ng’s Machine Learning class on Coursera. He also explains things intuitively before jumping into the math. Even when he uses math, he makes sure you understand the notations and what equation means.

Then you might prefer my

https://news.ycombinator.com/item?id=21301117

here.

I carefully define all symbols. I keep the math really simple; the only prerequisite is matrix multiplication; don't need matrix inverse. For matrix transpose, I define that. For squared length of a vector, I define that, too. I don't use calculus, derivatives, or probability. I derive the normal equations in just two lines of matrix algebra.

Maybe the target audience are Mathematicians or Physicists in the mind of the author