Исправьте ошибки в предложениях.

1. He is the most oldest student in his group.

2. You are older then me.

3. My car is more better than his.

4. It is one of most beautiful places in our country.

5. These flowers are more cheap than those ones.

6. I want do something most interesting.

He is the oldest student in his group. (ошибок нет)

You are taller than me. (Тут нужно вместо then, вставить-than(чем).

My car is better than his. (ошибок нет)

It is one of the most beautiful lakes in the world. (правильно)

These flowers are cheaper than those ones. (cheap - это односложное слово и следует использовать окончание сравнительной степени)