There are/ there is four backpacks
There are four backpacks
There is/ there are a table
There is a table
Is there / Are there a teacher in the class?
Is there a teacher in the class? - Yes, there is
Is there/ Are there five hippos?
Are there five hippos? - Yes, they are
There is/ there isn't a horse in the zoo
There isn't a horse in the zoo
Is there/ Are there six children in the playground?
Are there six children in the playground? - No, they aren't