Total Sales by Selected Categories =
CALCULATE(
    SUM(Sales[Amount]),
    TREATAS(
        VALUES(ProductLookup[Category]),
        Product[Category]
    )
)

Sales for Red Blue White =
CALCULATE(
    SUM(Sales[Amount]),
    TREATAS(
        {"Red", "Blue", "White"},
        Product[Color]
    )
)

Sales by Period Selected =
VAR SelectedPeriods = SUMMARIZE(DateLookup, DateLookup[Year], DateLookup[Month])
RETURN
CALCULATE(
    SUM(Sales[Amount]),
    TREATAS(
        SelectedPeriods,
        Date[Year],
        Date[Month]
    )
)

Sales Intersected =
CALCULATE(
    SUM(Sales[Amount]),
    KEEPFILTERS(
        TREATAS(
            VALUES(Lookup[ProductCode]),
            Product[Code]
        )
    )
)

Count Customers in Selected Regions =
CALCULATE(
    DISTINCTCOUNT(Customer[ID]),
    TREATAS(
        VALUES(RegionLookup[RegionName]),
        Customer[Region]
    )
)