Obama cheese
Mmm, oh no, I don't understand this is when you're so confused by something simple it makes you want to cry.
I tried to do my math homework and it was like mmm, oh no, I don't understand this.
When my sister asked me to help her with her science project, I just said mmm, oh no, I don't understand this.
The teacher asked me a question and I just stared at him like mmm, oh no, I don't understand this.