To solve this question, we need to know how many balls there are altogether in Cliff's bag. In total, there are 20 balls (8+7+5). We know that 8 of the balls are greens, so by subtraction (20-8) we can tell that the probability of picking a ball that is not green is 12/20. Usually, we try to simplify the fractions as much as possible before presenting it as an answer. In this case, we can divide both top and bottom numbers of the fraction by 4 to get the simplified answer 3/5!