How do i create a function to give me the following mathematical formula:

(a+b+c+d+e+f)/N * 6/N

Where a-f are numbers between 0-9 inclusive and importantly N = 6 - (the
number of values a-f that are '0')

example

numbers = 1 3 5 7 0 8

Then N= 5

So answer is 24/5 *6/5 = 5.76

Thanks

Simon
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simon