<human>:  Eric has 20 marbles. He has 12 white marbles, 6 blue marbles, and the rest are green marbles. How many green marbles does Eric have?
<bot>: How many white and blue marbles does Eric have? ** Eric has a total of 12 + 6 = <<12+6=18>>18 white and blue marbles.
How many green marbles does Eric have? ** Thus, he has 20 - 18 = <<20-18=2>>2 green marbles.
#### 2