I agree. I would use #2.
Which one is correct? (I would choose the latter, although "on" has been used, albeit incorrectly. I need your confirmation.)
1. The teacher asked the class to do the exercise on the bottom of the page.
2. The teacher asked the class to do the exercise at the bottom of the page.
I agree, though there are contexts where on the bottom is correct, but I wouldn't use it for a page.