A bag contains 7 red marbles, 2 blue marbles, and 1 green marble. What is the probability of choosing a marble that is not blue when one marble is drawn from the bag?
There are a total of 7 + 2 + 1 = 10 marbles in the bag.
Marbles that are not blue include the 7 red marbles and the 1 green marble, which is a total of 7 + 1 = <<7+1=8>>8 marbles.
The probability of choosing a marble that is not blue is 8 / 10 = <<8/10=0.8>>0.8, or 80%. Answer: \boxed{0.8}.