Honestly, I don't understand why you teacher would yell at you and classmates laugh at you. Idk maybe becuase you can solve it with a calculator, idk.
But the answer: 0.818181......
I don't have the personality of shallow people so I don't get why people act like that. A teacher is there for you whenever you have questions, so I dont like when teachers act that ridiculously. Now most students are mean and have the metal capacity of a peanut, so its understandable why they act so shallow. So my advice is don't pay attention to them.
Anyway, the answer is 0.818181....
Hope this helps ;P