Dim x As String, p As String
        Dim a, b, y As Single, n As Integer
        x = LTrim(TextBox1.Text)   例如：" 1+2"  取得“1+2”
        a = Val(x)                 这一步取到 "1" 并且转化为数值类型
        n = Len(LTrim(a))          为什么这里又要去掉前面的空格？不是前面去过空格才转化为数值类型的“1”的吗？那应该前面是没有空格的吧？
                                   而且去掉这里的“Ltrim”后，运算就出错，求问原因？大谢!!!!
      

        p = Mid(x, n + 1, 1)
        b = Val(Mid(x, n + 2))
        If p = "+" Then
            y = a + b
        ElseIf p = "-" Then
            y = a - b
        ElseIf p = "*" Then
            y = a * b
        ElseIf p = "/" Then
            y = a / b
        End If
        TextBox2.Text = y

自己顶一下，纠结了很久了。高人快点告诉我，很小的问题，一点就通的！！！！

都没有人来解答疑惑么。。。