# File lib/spreadsheet/worksheet.rb, line 248
   def write_number(row, col, num, format=nil)
      record  = 0x0203
      length  = 0x000E
      
      xf_index = XF(row,col,format)

      raise MaxSizeError if row >= RowMax
      raise MaxSizeError if col >= ColMax

      @dim_rowmin = row if row < @dim_rowmin
      @dim_rowmax = row if row > @dim_rowmax
      @dim_colmin = col if col < @dim_colmin
      @dim_colmax = col if col > @dim_colmax

      header    = [record,length].pack("vv")
      data      = [row,col,xf_index].pack("vvv")
      xl_double = [num].pack("d")

      if BigEndian
         xl_double.reverse!
      end

      append(header,data,xl_double)
   end