have to do, must do
やらなくちゃならない家事がいくつかあるんだ。
I have a few household chores I need to do.
なんで僕がやらなくちゃいけないの。
Why do I have to do it?
今は宿題をやらなくちゃいけないんだよ。
I have to do my homework now.
止血するために何かやらなくちゃ。
I need to do something to stop the bleeding.