are these sentences correct?

[Sunshine]

Are these sentences correct please? (apart from the accents)

Les maths sont interessantes.

Le pain et le fromage, c'est delicieux.

[George Hunt]

Yes I think so .

[Lionel]

I think both are correct.

Howether, we are unlikely to say the first sentence, "les maths sont intéressantes".

These sound more natural to me :
"Les mathématiques sont intéressantes"

"Les math(s?), c'est intéressant"

[Bon Gabriel]

Hello

These sentences are correct. Mathematical is a noun and it accords with the interesting adjective. This is why you've done well to add an 'e' on this. Indeed, interesting is an adjective that arouses interest and it accords with the "mathematical" name.

We always say "Mathematics" (plural) is why the adjective "interesting" takes an "s".

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[Charles D]

How about another construction?---

         Les maths m'interessent.  

[Grégory]

Correct too

[George Hunt]

Also possible:

          "Les maths , ça  m'intéresse" ,  I think.

[Charles D]

Yes, but even in this construction, if "maths" is plural in French (as it is in the Queen's English but not in American English where "math" is singular), would is be Les maths, ces m'intéressent?

[Grégory]

No, we say "Les maths, ça m'intéresse" and that works with any plural noun "Les animaux, ça m'intéresse", "Les avions, ça m'intéresse", "Les langues, ça m'intéresse" etc. Sometimes there's a semantic agreement which prevails over the grammatical one. It's uncommon but it exists. Here those plural nouns are seen as single realms that's why we use singular.  

[Charles D]

Ah, merci pour cette explication.