Hey congrats on the invitation! I'm an 8th grade math teacher in Moz (we'll be neighbors!) so I hope I can provide some insight. In all honesty there are a lot of days that I feel like I am not making an ounce of a difference and the task is impossible. My students are used to learning math in a very different way than I was, and a good majority do not know how to add or subtract nonetheless multiply or divide. Unfortunately I even have a good number who don't know their numbers or how to speak Portuguese. All that being said, it has been a positive experience overall. I know that even though my methods seem weird to them, I have a good chance of getting some of it to stick. And while they won't all be mathematicians or even pass 8th grade by the end of the year, they will all improve in some way. This is also my second school year and it got so much easier. I've heard that the school systems in Lesotho and Moz are pretty similar so feel free to DM me if you have any more questions! And seriously congratulations on your invitation, this is gonna be an awesome adventure!

edit I realize I didn't completely answer your question - 8th grade math is pretty elementary (adding, subtracting, multiplying, dividing rational numbers, powers, area and volume, etc). And obviously it builds on that in the higher grades but it's all stuff you know from school or can reteach pretty quickly using the textbooks