Japanese Grammar for Obligation ~nakute wa ikenai/naranai/dame (~なくてはいけない/ならない/だめ)

Hello, we meet again, with me riizhu^^, let's learn Japanese language online, we learned prohibition grammar in Japanese yesterday, and today we are going to learn a grammar for obligation in Japanese language. Maybe some of learners think to make an obligation just change the negative to positive, isn't it? but, in Japanese we will involve double negatives which create an affirmative meaning. Let's learn.

Grammar ~nakute wa ikenai/naranai/dame (~なくてはいけな/いならない/だめ)

JLPT Level: N4
Meaning: Must/have to
Formula: Negative te form + wa + ikenai/naranai/dame

Must learn before: negative te form conjugation
Note: dame=casual, ikenai/ikemasen=formal, naranai/narimasen=used in prohibition that apply to more than one person like rules or policies
Sentence example:

この文法を勉強しなくてはいけない
kono bunpou o benkyou shinakute wa ikenai
You must learn this grammar
毎日学校に行かなくてはなりません
mainichi gakkou ni ikanakute wa narimasen
You have to go to school everyday
お金が持ちたければ働かなくてはだめだよ
okane ga mochitakereba hatarakanakute wa dame da yo
If you want to have money you must work
図書館は静かじゃなくてはならない
toshokan wa shizuka janakute wa naranai
The library must be quiet

Yeah, the lesson today is finished^^, I hope you can understand my brief explanation, I think you will understand the grammar well, and then you forget the lesson or not It depends on how often you practice the lesson, practice makes perfect.