ChatGPT is so bad

I asked my students to take a ChatGPT test (a mock exam with questions covered in class) and compare the results. About half found that ChatGPT was scoring in the 30th percentile. After confirming ChatGPT's performance on the mock exam, I decided to use ChatGPT in class to see how well it would do on the questions we were going to discuss. It responded, but was incorrect every time. I didn't realize it was so bad.