Do you mean how many species, because I don't think anyone can organize a census to ask all the adult amphibians how many children they have.
One.
Several
many
After fish, amphibians were the next group of creatures to evolve on Earth. Amphibians are cold-blooded vertebrates that can live both on land and in water. They were the first vertebrates to colonize terrestrial habitats.
Amphibians can live on land and in water.
The animals which live both on land as well as in water are called Amphibians.
Japanese amphibians
Amphibians are egg layers.
Amphibians live everywhere except in permanent deserts and the poles.
On what planet? Amphibians are alive and well on Earth.
Amphibians can live in both land and sea.
Reptiles live on dry land; amphibians live on land as well as in water.