excel - 実行時エラー 13

Question

Option Explicit

Sub value()

    Dim mynumber As Integer, mysum As Integer, myextra As Integer
    mynumber = Range("A2:A17")
    myextra = Range("B2:B17")
    mysum = mynumber * myextra
    MsgBox ("mysum")

End Sub

なぜ私は得るのRun time Error 13ですか？