Adblock Plus (and similar software) only blocks ads that are embedded within the actual pages that you're seeking to view. (e.g. the ads down the right-hand-side of this page if you're viewing the 'non-mobile' version of this site).
If you're suddenly getting loads of other ads (such as pop-ups), that aren't actually part of the pages you're looking at, then you've got malware on your tablet (which programs such as Adblock Plus won't get rid of).
You need to download, install and run this:
https://www.malwarebytes.org/mobile/
(Important: That's a free program, from a reliable source but if - during the installation process - there's an option to take a free trial of a paid-for product, make sure that you deselect it)