The Education In the Third World Countries

I have a dream of being a math teacher in the future so I cares about the status of education status in everywhere.There is a fact that as of 2012, 31 million primary-school pupils worldwide dropped out of school. An additional 32 million repeated a grade.In big and developed countries, the education is very advanced. People are highly educated. But the education in the third world countries is pretty backward.  
There are lots of factors cause this issue. A lack of funding of the education may cause the poor families not able to afford the tuition fee for their children.Not only the money problem, in many places, the lack of teachers or having untrained teachers is a bigger problem. Most teachers do not want to go to a poor place to teach so although there are some children, there is no efficient way for they to study. In addition, poor places may have few classrooms and learning materials. The problem of external facilities is hard to deal with.
So the education should not be develop fast only in the rich countries, people need to pay more attention to the education in the third world countries in order to make people their educated and happy.