Imagine you want to play with your favorite toy, but it's really high on a shelf. Your dad could just get it for you, but he wants you to try to reach it yourself because that's the least restrictive way for you to learn and grow.
In the same way, when kids go to school, their teachers want to help them learn and grow in the least restrictive environment. This means that they want to help students be in a classroom that is just right for them. If a student has a hard time seeing the board, the teacher might put them in the front row where they can see better. If a student has a hard time focusing, the teacher might give them a special seat where they can concentrate.
Sometimes, a student might need more help than just a special seat or extra time on a test. In that case, the teacher and the student's family might get together to decide if the student needs extra support, like a teacher's aide, to help them learn. They might also talk about whether the student should be in a classroom with other kids who need extra help or in a regular classroom with just a few extra supports.
The goal is to help every student learn and grow in the best way possible, in a classroom that is comfortable and supportive for them. That's what the least restrictive environment is all about!