Make the number bold

Lets say I have a number 4,33916511 and I need to make the third number after comma bald. In this case to make number 9 bald. Maybe anyone could help me?

try this:

Sub bold()
iPos = WorksheetFunction.Find(",", Range("A1"))
With Range("A1").Characters(Start:=iPos + 1, Length:=1).Font
    .FontStyle = "Bold"
End With
End Sub

Cheers!!