How do a add a group of numbers in reverse until a condition is met?

[Water Billing]

I am trying to add a group of numbers together until I reach a 0 in a cell; however, I am starting with the last number in a column and going in reverse.

[TABLE="width: 10"]
<tbody>[TR]
[TD]100[/TD]
[/TR]
[TR]
[TD]200[/TD]
[/TR]
[TR]
[TD]300[/TD]
[/TR]
[TR]
[TD]0[/TD]
[/TR]
[TR]
[TD]450[/TD]
[/TR]
[TR]
[TD]200[/TD]
[/TR]
[TR]
[TD]600[/TD]
[/TR]
</tbody>[/TABLE]

i.e. I would like to start with the last number (600) and add until I reach a zero (600+200+450). Can someone help me? Thank you.

 

[Marcelo Branco]

Welcome to Mr Excel forum

Try


[Table="class: grid"][tr][td="bgcolor: #DCE6F1"][/td][td="bgcolor: #DCE6F1"]

A​

[/td][td="bgcolor: #DCE6F1"]

B​

[/td][td="bgcolor: #DCE6F1"]

C​

[/td][/tr]
[tr][td="bgcolor: #DCE6F1"]

1​

[/td][td]

Numbers​

[/td][td][/td][td]

Formula​

[/td][/tr]

[tr][td="bgcolor: #DCE6F1"]

2​

[/td][td]

100​

[/td][td][/td][td]

1250​

[/td][/tr]

[tr][td="bgcolor: #DCE6F1"]

3​

[/td][td]

200​

[/td][td][/td][td][/td][/tr]

[tr][td="bgcolor: #DCE6F1"]

4​

[/td][td]

300​

[/td][td][/td][td][/td][/tr]

[tr][td="bgcolor: #DCE6F1"]

5​

[/td][td]

0​

[/td][td][/td][td][/td][/tr]

[tr][td="bgcolor: #DCE6F1"]

6​

[/td][td]

450​

[/td][td][/td][td][/td][/tr]

[tr][td="bgcolor: #DCE6F1"]

7​

[/td][td]

200​

[/td][td][/td][td][/td][/tr]

[tr][td="bgcolor: #DCE6F1"]

8​

[/td][td]

600​

[/td][td][/td][td][/td][/tr]
[/table]

Formula in C2
=SUM(INDEX(A2:A8,LOOKUP(2,1/(A2:A8=0),ROW(A2:A8)-ROW(A2)+1)):A8)

Hope this helps

M.