Menurut guru, saya harus belajar lebih serius supaya lulus ujian matematika.

Menurut means according to or in the opinion of.

So Menurut guru means According to the teacher or In the teacher’s opinion.

Structure:

• menurut + person/source
• Menurut guru = according to the teacher
• Menurut saya = according to me / in my opinion
• Menurut dia = according to him/her

This is a very common way to introduce someone’s view or advice.

Indonesian often leaves nouns less specified than English does.

So guru can mean:

• the teacher
• a teacher
• my teacher / our teacher depending on context.

If you want to be more specific, you can say:

• guru saya = my teacher
• seorang guru = a teacher
• guru itu = that teacher / the teacher

In this sentence, Menurut guru is natural if the context already makes it clear which teacher is meant.

Harus most directly means must or have to. It often sounds stronger than English should.

So:

• saya harus belajar = I must study / I have to study

However, in translation, English sometimes uses should if the tone is softer or more natural in context.

Important nuance:

• harus = obligation / necessity
• sebaiknya = should / it would be better to
• perlu = need to

So if the Indonesian sentence uses harus, the idea is stronger than simple advice.

Both relate to learning/studying, but they are not used in exactly the same way.

• belajar = to study, to learn
• mempelajari = to study something in a more direct, object-focused way

In this sentence:

• belajar lebih serius = study more seriously

That sounds natural because the focus is on the act of studying, not on a specific object.

Compare:

• Saya harus belajar. = I have to study.
• Saya mempelajari matematika. = I study mathematics / I am studying mathematics.

You usually would not say mempelajari lebih serius by itself here.

Literally, lebih serius is more serious.

But in Indonesian, adjectives are often used where English would prefer an adverb. So:

• belajar lebih serius = study more seriously

This is very normal Indonesian.

You may also hear:

• belajar dengan lebih serius = study more seriously

That version is a little more explicit, but the original sentence is completely natural.

Supaya means so that or in order that.

It introduces purpose:

• Saya harus belajar lebih serius supaya lulus ujian matematika.
• I must study more seriously so that I pass the math exam.

Common similar words:

• agar = so that, in order that
• biar = so that, let; often more informal in some contexts

In many situations, supaya and agar are interchangeable.

Because the subject is understood from context.

Full version:

• Menurut guru, saya harus belajar lebih serius supaya saya lulus ujian matematika.

But Indonesian often omits repeated subjects when they are already clear. So the shorter version is more natural:

• ...supaya lulus ujian matematika

The understood meaning is:

• ...so that I pass the math exam

This kind of omission is very common in Indonesian.

Because lulus is used differently depending on what follows.

Common patterns:

• lulus ujian = pass an exam
• lulus sekolah / lulus dari sekolah = graduate from school
• lulus kuliah = finish/graduate from college

So for exams, lulus is commonly followed directly by the exam:

• lulus ujian matematika = pass the math exam

Using dari here would usually sound unnatural.

Ujian matematika means math exam.

The order is:

• ujian = exam
• matematika = mathematics

In Indonesian, noun + noun combinations often work like this:

• buku sejarah = history book
• guru bahasa Inggris = English teacher
• ujian matematika = math exam

So the second noun describes the first.

Yes, in this sentence, agar would sound very natural too.

• Menurut guru, saya harus belajar lebih serius agar lulus ujian matematika.

This means essentially the same thing.

Very roughly:

• supaya = common and natural
• agar = also common, sometimes felt slightly more formal or careful
• In many real situations, there is little practical difference

Sometimes yes, but it depends on context.

Original:

• Menurut guru, saya harus belajar lebih serius supaya lulus ujian matematika.

Possible omission:

• Menurut guru, harus belajar lebih serius supaya lulus ujian matematika.

That can work if it is already very clear that the speaker means I. But without context, leaving out saya can sound less clear.

Indonesian often omits subjects, but learners should keep saya until they are comfortable with when omission sounds natural.

Yes, it is very typical.

Breakdown:

• Menurut guru, = According to the teacher,
• saya harus belajar = I must study
• lebih serius = more seriously
• supaya lulus ujian matematika = so that I pass the math exam

So the sentence flows in a very normal Indonesian way:

1. source/opinion
2. subject
3. obligation
4. verb
5. manner
6. purpose

Nothing in the word order is unusual.

Yes, it sounds natural.

It is a clear, standard sentence. A native speaker might also say slightly different versions, such as:

• Menurut guru, saya harus belajar lebih giat supaya lulus ujian matematika.
• Kata guru, saya harus belajar lebih serius supaya lulus ujian matematika.
• Menurut guru, saya harus belajar lebih sungguh-sungguh agar lulus ujian matematika.

Nuance:

• lebih serius = more seriously
• lebih giat = more diligently
• lebih sungguh-sungguh = more earnestly / more seriously

But your original sentence is perfectly normal and correct.