"My grandmother walks slowly."

Translation: Moja babcia chodzi wolno.

[IcecreamBadger8]

I said "Moja babcia idzie powoli" and it was counted as incorrect although "idzie" and "chodzi" means the same thing.

[immery]

doulingo is rather consistent in making you translate "she walks/goes= chodzi and she is walking/going = idzie.

[Arnoldpitt]

Is there a significant difference between wolno and powoli?

[Jellei]

"wolno" has other meanings, but both mean "slowly". In terms of "slowly", the difference seems rather stylistic to me... frankly, I'd go with "powoli" here myself.