What kind of experience is it that my sister is a school scum?

My academic performance has been very good. I have been winning various awards since I was a child, and my academic performance in high school has not deteriorated. Finally, I was admitted to a good university. I have been getting various scholarships during my college years, so I have always felt that learning is not a very difficult thing. I naturally think that my sister can also get good grades, make a name for herself in school, and get various scholarships with her academic performance.

But my sister really let me down. My sister has been a scum since primary school, and her grades have always been at the bottom of the class. My mother is often invited to school because the teacher wants to talk to my mother about my sister's grades. Once I went to school to meet the teacher instead of my mother. The teacher has been telling me all kinds of problems in my sister's study. As a student with good grades, I really can't understand what the teacher said.

I also attended the parent-teacher conference instead of my mother. When I was at school, I was very happy at every parent-teacher meeting, because my grades were always among the best and I was always praised at the parent-teacher meeting. But the parent-teacher conference I gave my sister was the most humiliating one I have ever experienced. Because my sister is at the bottom of the class in any subject, the teacher praised many people, but my sister is still not on the praise list. I think I'll leave the parent-teacher conference at once.

I also wanted to tutor my sister. But every time I help her with her homework, I will be crazy because she will make many basic mistakes in her homework. I want to correct them one by one, but my sister always looks puzzled. What annoys me most is that I tell her math problems. She doesn't even know a lot of basic knowledge and basic formulas. I told her a question three or four times, but she still didn't understand it. Sometimes she gets it, but she still makes many mistakes when she does the problem. I get angry every time.