I'm going to ditch my table in a group math quiz
Why would you want to leave them behind?
I don't think I'm doing well in this quiz. So no reason to stay.
You shouldn't ditch your partners. Even if you think you aren't going to do well, your group is counting on you to be there and participate.
Who cares? I don't care about them.
Ditching your partners will make you appear unreliable. This will affect your relationship with them in a negative way moving forward.