Hi there, I got two decisions to this quest:
(1)
Result =
Var ThisDate = [Date]
Var ThisRegion = [Region]
Return
SUMX(FILTER(table, table[Date]=ThisDate && table[Region]=ThisRegion),
table[Ratio])
(2)
Result =
SUMX(
FILTER(
ALL('Table'),
'Table'[Date] =EARLIER ('Table'[Date])
&& 'Table'[Region] = EARLIER('Table'[Region])),
'Table'[Ratio])