2) there isn’t a computer on the table

There is a computer on the desk

3)there aren’t books on the sofa

There are books in the bookcase

4)there aren’t two sinks in the kitchen

There is one sink( a sink) in the kitchen

5)there aren’t five armchairs in the living room

There are two armchairs in the living room

6)there isn’t a picture on the wall

There are three pictures on the wall