All the regular rules of multiplying and dividing apply here. However, there is one important detail that needs to be mentioned, even if it can't be perfectly explained.

Based on how you add and subtract them, you might expect that the result of -4 • -4 is -16, but you'd be wrong: it's 16. When multiplying or dividing, two negative numbers make a positive number!

This can be broken down to make some sense. Multiplying is the result of adding something to 0 a certain number of times. To get -16, you add -4 to 0 4 times, not -4 times. And since the opposite of adding is subtracting, you could say that you subtract -4 from 0 4 times, giving you 16.

It's logical, but it's a stretch to say that it is intuitive. It will take time to develop this skill.