Question

Why do female frogs produce eggs in large in numbers ?

Answer 1

They lay eggs in water.These eggs do bot have any hard layer.So,they are very delicate.Many of the aquatic animals also consume these eggs.So, a large amount of eggs get destroyed.
Now male frog also produce sperms in a large amount in water.So, to ensure fertilisation of a few of them they lay eggs in large numbers.....

Answer 2

By producing lots of eggs, there is a better chance of the species surviving.