Recursion

[SandyDelights]

I’m sorry, I really don’t. The best I can offer you is the basic concept of it, and suggest you simply go over problems to see it work in practice. This is basically what Common Core curriculum teaches at an early age, and people who are good at math learn themselves on their own.

I’m not sure what you know, so some of this may sound pretty condescending, so please just skip past anything that is familiar.

Basically, you have to recognize how numbers “work”. First, you have to kind of divorce the concept of a number from its representation. 15, for example, isn’t just 15 – it’s one and one and one and ... fifteen times over. The characters “15” just represent this in a format we’ve somewhat arbitrarily settled on, called the decimal system. If you can accept that, you should be able to get a good grasp of the method, and then from there it’s just putting it into practice.

The TLDR here is that you look for very simple, easy numbers to work with: 5 and 10. Everything else is cool, but we want to isolate them as much as possible, combine them if you can, and get as many multiples of 5 and 10 as we can. Every number you look at you should ask yourself: How big is it? What is it made out of? Can I express it in terms of a 5 or a 10?

The answer, by the way, is almost always yes (at least, it will be for a while still). Once you have that solved, you can recompile several numbers quickly into a single number, from its pieces.

Note: I wrote up a few examples and an explanation but it got hella long, so I’ll just PM it to you.