Averaging numbers

[PMRetired2012]

I have a row of 10 numbers and each week i add numbers. What i want to do is have a formula that will average the last 4 numbers in that row of numbers when i add numbers to the row of numbers. So what im saying is i want to be able to always adverage the last 4 number that have been entered.

Thanks

 

[sapionapio]

Hi

=AVERAGE(INDEX(A:A,COUNT(A:A)),INDEX(A:A,COUNT(A:A)-1),INDEX(A:A,COUNT(A:A)-2),INDEX(A:A,COUNT(A:A)-3))

Have a nice day!

 

[PMRetired2012]

What do I put in the part that says A1:A1 and also does the -1 mean the last 4 numbers to be averaged? So my row of numbers to adverage is b3 thru b13 should that go where the A1:A1 is? And if I want it to adv the last 4 which would be b10 thru b13 would I use -4 instead of -1?

Thanks

 

[AhoyNC]

Another option.

Excel Workbook
	A	B	C	D
1
2		Data
3		45		Average
4		36		last 4
5		25		51
6		36
7		21
8		12
9		58
10		69
11		54
12		56
13		25
Sheet