Math on last non zero cell in a row

[pfaustino]

I have a spreadsheet with columns that represent months, and rows that represent numbers. I want to have one final cell in the row that represents the value of the first cell in the row minus the last non zero entry in the row. Would a formula be best? I’m an excel novice and am running into circular math errors. Thanks for any guidance you can provide.

 

[maabadi]

Welcome to MrExcel Message Board.
Try this:

Book1
	A	B	C	D	E
1	Jan
2	45		40
3	12
4	5
5	18
6	4
7	15
8	22
9	12
10	27
11	19
12	0
13	5
14	0
15	0
16	0
17
Sheet1

Cell Formulas
Range	Formula
C2	C2	=A2-LOOKUP(2,1/($A$2:$A$16 <> 0 ),$A$2:$A$16)