If you want to calculate the mean of several products, there is an easy way to do it - just add all of those numbers and divide the product by the number of items.
So, here is how to do it:
10,126 + 9,999 + 12,398 + 12,007 + 4,567 = 49,097
Now divide that number by 5 (the number of numbers):
49,097 / 5 = 9,819.4
The correct answer is 9,819.4