If they are 9 by 9 's you might want to leave them, they could be asbestos. If not you can scrape them with agarden hoe or an actual scrapper. If there down good you need to get a heat gun (around $15.00) and do them one at atime. Lowes sells a floor levler (around $18.00) to level the hump. Going over the tiles isn't a bad thing. Also paint the black glue (cutback) with a cheep paint or left over paint, because it will be sticky.................Eric

Check this article out. It might be helpful to you like it was to me recently when we were doing the same project!

https://upfrontbathrooms.com/how-to-remove-tile-floor/