I am currently relearning basic math - including; fractions, decimals and percentages. I am learning from various different sources, and what gets me is that they only teach math in forms of methods. This bugs me because they teach you the 'how' and not the 'why'. There maybe a good method to divide two fractions with uncommon denominators, but there is no explanation of why the method works. I want to understand the process, not just learn it.
Question - are there any reliable educational sources that explain the logic behind the methods? Or in other words, is there a way to understand the nature of numbers and how they are calculated? In this way I can understand math, rather than just learning the methods to calculate numbers.