A. Is it hard to bake?

Baking is a little hard.​✔

​

B. I know.

=> Another way: Your sentence is okay and this is another way of saying it. 

Oh, I see. 

What day is it today?

​=> Another way: Your sentence is okay and this is another way of saying it.

What's the date today? 

It's September 23rd.✔​​​