Help identify my plant?

My plant is one that i got from my sisters school, the science labs were having a clear out and i ended up with a tropical plant, it has a stem of about a centimeter thick and arrow shaped jagged leaves, on each of the serrated edges of the leaves it grows a seedling, probably about 50 seedlings on a bigger leaf. If you knock the plant slightly these seedlings fall off and as they already have two leaves and a few roots they start to grow bigger within days. Kind of an odd plant but I've had it for a long time and I want to know what it is. Help?