Sub hoge1()
Dim v As Variant
Dim b As Byte
b = 1
v = v + 1
Debug.Print TypeName(v)
Debug.Print v
End Sub

Sub hoge2()
Dim v As Variant
v = True
v = v And 0
Debug.Print TypeName(v)
Debug.Print v
End Sub

Sub hoge3()
Dim v As Variant
v = "0"
v = v + 1
Debug.Print TypeName(v)
Debug.Print v
End Sub

うーん・・・