Or, for 3.50 coins each, either Shredder or Chess Genius for Android, then you play it on your smartphone on tablet, which is very comfortable and convenient. I know both myself, and its the way I play chess most of the time these days. The nice thing about Shredder is it has self-adapting difficulty level, it adapts to your own results over time. Beat the AI, and it adjust upwards, loose a lot, and it adapts downwards. It also plays "human" on lower levels, makes mild mistakes, nothing obvious, just is imperfect in a believable, human way. On Andorid, I like Shredder best. Its also a very good software - computer world champion several times, though that issi quite some tie ma ago. More tahn enough for me - and for you as well, I assume.
Find it in the Google Playstore and read the reviews. It is very much liked, for good reason. And it is very cheap.
Tablet:
Smartphone:
There are also (free) chess problem apps that challenge you with - well, chess problems, sorted by difficulty level or themes. Also a good way to get into it!