VLOOKUP function finds the row in range that has a first column similar to value. If @approximate is not true it finds the row with an exact equivilance. If @approximate is true, then the values must be sorted in order of ascending value for correct function; in this case it finds the row with value less than @value. It returns the value in the row found at a 1 based offset in @column columns into the @range.
Returns #NUM! if @column < 0. Returns #REF! if @column falls outside @range.