Some of us have had a problem syncing multiple Google Calendars to the iPad. Here's a fix:
Enable the Safari debug on your Mac.
Set the user agent to iPhone
Go to m.google.com/sync
Turn off JavaScript
Select your iPad device
Select your calendars (it should work)
Disable/re-enable your calendars through the Exchange account you established on the iPad
There you have it
Thanks to Eric et al on the Google Help forums
https://forums.macrumors.com/showthread.php?p=11604517#post11604517
I completed all of the steps and my calendars still won't sync. I created an Exchange account on my iPad for my gmail account and my calendars wouldn't show up. I have my gmail account set up on my iPad and the only calendar (out of like... 7) that shows up is the calendar I never use and has the same name as my account.
As a side note that may or may not be related to the issue; I can sync all of my gmail calendars to my iCal program on my MacBook Pro. I tried syncing my iPad to my iCal (via iTunes) and the gmail calendars that show up in iCal still will not show up on my iPad.
Does anybody have an suggestions or tips?