Can anybody tell me what does this macro do??

Sub DoGoalSeek()
'
' DoGoalSeek Macro
' Macro recorded 19/04/2011 by glittle
'

'
    Range("B4").Select
    ActiveCell.FormulaR1C1 = "5"
    ActiveSheet.Calculate
    Range("E30").Select
    Range("E30").GoalSeek Goal:=0, ChangingCell:=Range("B4")
End Sub