If you drive to UC Davis, please park your car to visitor parking lot 47, see the map here:
https://goo.gl/maps/fv7EUN47krYx8ccb7
You need to buy a parking ticket from the ticket machine in the parking lot, it costs $10.
If you can't find a parking spot in lot 47, then you can park to the Pavilion structure, see the map here: https://www.google.com/maps/place/Pavilion+Structure,+2+Dairy+Rd,+Davis,+CA+95616/@38.5397163,-121.7588089,18z/data=!3m1!4b1!4m5!3m4!1s0x80852906bdfc3157:0xd5b23245c2340a77!8m2!3d38.539715!4d-121.7581487
There you also need to purchase a ticket, and please remember to park to the designated spots for visitors.
The Math department is in MSB (math science building). see the map here https://www.google.com/maps/place/UC+Davis+-+Department+of+Mathematics/@38.5358467,-121.7547618,17z/data=!3m1!4b1!4m5!3m4!1s0x8085290fe30aaf99:0x4d71f93aea613300!8m2!3d38.5358425!4d-121.7525731