Using Sum and another function

[vmehta23]

Hello,

My data looks something like this:

Total Mobile Costs	Period
60	10
178	7
29	12
199	10
116	8
350	1
48	2
275	4
299	7
425	11
166	7
3	6
359	2
450	10
100	9
314	10
7	4
455	6
48	7
71	7

I am trying to sum the Total Mobile costs based on the current selected filter (I have a filter on the sheet to choose period 1-12). So I am trying to display the previous "Period"  from current selected Period number e.g I select from filter to show Period 10 so the formula show the sum of total mobile costs of Period 9.

This is the formula I thought might work but it doesn't...:

Sum({$<Period ={(Period)-1}>}[Total Mobile Cost])

Hope my issue makes sense!

Thanks

[sunny_talwar · Accepted solution]

Try this

Sum({$<Period = {$(=Max(Period)-1)}>} [Total Mobile Cost])

[vmehta23]

Works exactly as intended, thank you!