Not sure if anyone has used these videos before, but it’s always nice to have something explained by a third party.
Math Antics can be subscribed to on YouTube, but also has its own website with other resources. Some are paid ($20/year) but there are some free examples that might be useful.
I like Math Antics because of the simplicity of the explanation. Examples are given and numbers are manipulated in a clear, easy to understand manner.
Here’s an example-