1. There
is a boy and a girl in the playground.
2. There is a boy, a girl and an old man in the playground.
3. There is a boy and two girls in the playground.
4. There are two girls and a boy in the playground.
Some language experts now regard
there is as
a fixed, unvarying idiom that can precede a (plural) list of nouns so
long as the first noun is in the singular. However, the constructions
with a singular verb might attract criticism from old-fashioned purists.
(The Right Word at the Right Time)