Mark has 3 tanks for pregnant fish.  Each tank has 4 pregnant fish and each fish gives birth to 20 young.  How many young fish does he have at the end? Let's think step by step and output the final answer after "####".
user
He has 4*3=<<4*3=12>>12 pregnant fish
They give birth to 12*20=<<12*20=240>>240 fish
#### 240
Mark has 3 tanks for pregnant fish.  Each tank has 4 pregnant fish and each fish gives birth to 20 young.  How many young fish does he have at the end?
train