"My hand is smaller than my foot."
Translation:मेरा हाथ मेरे पैर से छोटा है।
I think the words offered for the English translation are wrong. It should translate as "My hand is smaller than my feet" , not "my foot".
To me both seem fine. मेरे here indicates the oblique case (because पैर is followed by से). पैर in plural oblique form would be पैरों if I'm not mistaken.
Why does DuoLingo have a problem with my answer, that I typed, मेरा हाथ मेरे पैर से छाेटा है I see nothing wrong with my spelling of छाेटा