Fingerplays and songs are a great way to help children learn basic math concepts. Here is one that I will be using in my storytime during the Spring season.
Five Little Ladybugs 
Five little ladybugs climbing up a door,
One flew away then there were four.
Four little ladybugs sitting on a tree,
One flew away and then there were three.
Three little ladybugs landed on a shoe,
One flew away and then there were two.
Two little ladybugs looking for some fun,
One flew away and then there was one.
One little ladybug sitting in the sun,
She flew away then there were none.