A golf ball is selected at random from a golf bag. If the golf bag contains 6 orange balls, 10 green balls, and 9 red balls, find the probability of the following event. The golf ball is orange or green. The probability that the golf ball is orange or green is (Type an integer or a decimal rounded to three decimal places as needed.)

Step 1 ：Define the number of each color of golf balls: \(orange\_balls = 6\), \(green\_balls = 10\), \(red\_balls = 9\)

Step 2 ：Calculate the total number of balls: \(total\_balls = orange\_balls + green\_balls + red\_balls = 25\)

Step 3 ：Calculate the probability of the golf ball being orange or green: \(probability\_orange\_or\_green = \frac{orange\_balls + green\_balls}{total\_balls} = 0.64\)

Step 4 ：Final Answer: The probability that the golf ball is orange or green is \(\boxed{0.64}\)