Using variable in Range in Sub

[Orada]

Hi

I seem to be confusing the use of variables in ranges somehow so would appreciate help. The code below is intended to highlight one row as defined by the variable r which is a for next counter, but instead it highlights the whole sheet.

Range("A" & r & ":S" & r).Select
    With Selection.Interior
        .ColorIndex = 15
        .Pattern = xlSolid
    End With

The routines below to clear certain columns and remove all formatting before running work fine but these variables are not part of a loop counter.

    Range("A" & firstrow & ":A" & lastrow).Select
    Selection.clearcontents
    
    Range("R" & firstrow & ":S" & lastrow).Select
    Selection.clearcontents

    Range("A" & firstrow & ":S" & lastrow).Select
    Selection.Interior.ColorIndex = xlNone

Some insight from the more experienced as to what I am doing wrong would be greatly appreciated.