So lately, I've decided to start relearning math because past 6th grade, things stopped making sense and I got frustrated and completely gave up on the subject. The thing that has always prevented me from advancing in this subject is not knowing why so many things are the way they are in math, and these things are never explained clearly.

Why are formulas written the way they are? How did you know to add that number there? How does this make any sense in reality? What's the reason behind every step of solving whatever this problem is?

Here are examples of my struggle:

I asked earlier in a thread that got deleted as I was about to ask someone for clarification. I relearned how to add 2 fractions and while it was easy, the way it was written puzzled me. There was this in the instructions, "This is basically multiplying each fraction by 1" and it looked like this:

\left(\frac{1}{3} \times \frac{7}{7}\right) + \left(\frac{4}{7} \times \frac{3}{3}\right) = \, ?[/math]

Why isn't it just written something like:
$\left(\frac{1}{3} \times 7\right) + \left(\frac{4}{7} \times 3\right) = \, ?$? If $\frac{7}{7} = 1$, then I am interpreting the formula based on the instructions and written form as $\left(\frac{1}{3} \times 1\right) + \left(\frac{4}{7} \times 1\right) = \, ?$.

There was also the intro to imaginary numbers precalculus on Khan Academy where the guy was explaining the definitions of $i$. He explains, "$i$ is equal to the principal square of negative one" and wrote $i^2 = -1$ without any real background info on why this is the way it is. He just explains what they are. What does it really mean?

This is also my first time ever using TeX, so I apologize in advance if it doesn't post correctly.