' 宣言していない変数を使用不可にする．
Option Explicit

Sub MainProc()

    Dim a1 As Double, a2 As Double
    Dim b1 As Double, b2 As Double
    Dim b3 As Double, b4 As Double

    a1 = ActiveSheet.Range("A2").Cells(1, 1).Value
    a2 = ActiveSheet.Range("B2").Cells(1, 1).Value

    b1 = a1 + a2
    b2 = a1 - a2
    b3 = a1 * a2
    b4 = a1 / a2

    ActiveSheet.Range("E2").Cells(1, 1).Value = b1
    ActiveSheet.Range("E2").Cells(2, 1).Value = b2
    ActiveSheet.Range("E2").Cells(3, 1).Value = b3
    ActiveSheet.Range("E2").Cells(4, 1).Value = b4

End Sub