In our example ISBLANK(Range) creates the following array. MATCH(TRUE,{FALSE;FALSE;TRUE;FALSE;FALSE;TRUE;FALSE},0) then looks for the first exact match to a TRUE value within this array. This returns the value 3 since the first TRUE value is in the 3rd position and this is our first blank cell in the range.

How To Find The Position Of The First Blank Cell In A Range - 16