There's no special math you need to learn. You have a system of equations (sum and product) that you can manipulate to reduce the Big(O) of your algorithm. Not sure if that helps (without giving the answer away).

The math and algebra behind the solution (at least the most popular and efficient solutions) are not so complicated.

On the side note always format your code using Markdown. An extract from Markdown link -

The Codewars comment system allows for Markdown that follows GitHub Flavored Markdown, you can read about all the bells and whistles through the link.

Try using row = row.concat("\\n"); Instead of row = row.concat("\n");. Then check your output with the text fixture code manually.

First test creates 2 blocks and asks for values of 1st one. Your error message Expected: 3, instead got: 1 indicates the 2d block you created crashed data of 1st one. (3 is value of 1st Block width, 1 is value of 2d Block width)

So it seems the problem is with your code.
Good luck!

which language ?