怎样保留三位小数？？（求助！！）

路边

Sub nn()
Dim a, b As Double
Dim c As String
a = 10006466.20023
b = FormatNumber(a, 3)
c = FormatNumber(a, 3)
MsgBox (b)
MsgBox (c)
b = Int(a * 1000 + 0.5) / 1000
MsgBox (b)
End Sub

显示结果为10006466.2或者10，006，466.200

问怎样才能使结果为10006466.200

请各位仁兄帮忙！！

czlj2008

b = Int(a * 1000 + 0.5) / 1000
b=format(b,"0.000")

路边

谢谢!!!

swjtu2000

round(value,n)

n为保留位数