To find the average, you would add 23, 18, 16, 24, 27, and x. Then you would divide the answer by 6 (because there are 6 numbers), and that would be your mean.
Let's draw that mathematically:
Then, we'd simplify to figure out x:
So, the score for the 6th game was 12.
Remember, the key is to stripping the problem of words and putting into mathematical terms for easier understanding.