Do Upper division courses transfer?

I am a UC to UC transfer applicant and I took some upper div classes at my current UC’s. Would those classes transfer and give me credit at my new UC if I were to be admitted? Note: I will apply as a math major and the upper div courses I take at my current UC will definitely be offered at the new UC because they are quite common courses.

Yes, they do. In fact, you should be careful with that and talk to a counselor or UC representative about that because it can prevent you from being admitted if you’ve taken too many upper-division courses.