RosettaCodeData/Task/Temperature-conversion/Excel/temperature-conversion-2.excel

FROMKELVIN
=LAMBDA(toUnit,
    LAMBDA(n,
        LET(
            REM, "Valid units :: C, F, R, K",

            CONVERT(
                n, "K",
                IF("R" = toUnit,
                    "Rank",
                    toUnit
                )
            )
        )
    )
)