求大神帮忙做题，实在不会

vb.net 写的 参考一下
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a As Short
Dim b As Single
Dim t As Short
Dim m As Single
a = CShort(TextBox1.Text)
b = CSng(TextBox2.Text)
t = CShort(TextBox3.Text)
m = a * (1 + b) ^ 12 ^ t / (t * 12)
TextBox4.Text = Format(m, "0.00")
End Sub