Multiply medicine - S1.E129

Nobita only has one cake left so Doraemon treats it with Peipei medicine to make more but warns Nobita every single cake must be eaten as any remaining cakes double every 5 minutes. Nobita cannot eat them all and suddenly finds himself with lots of cakes on his hands. Even his mom and friends cannot manage them all so as the cakes begin to pile up, and would cover the Earth in just a day, so Doraemon sends them into space.