Intent()객체를 생성한다
Intent(from Acticcity , to Activity)
기본 형식 (send)
val intent = Intent(this@Intent1, Intent2::class.java)
intent.putExtra("number1", 1)
intent.putExtra("number2", 2)
startActivity(intent)
(give)
Intent객체 생성
intent.getIntExtra("number1",0)