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Yes I think so .
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"
How about another construction?---
Les maths m'interessent.
"Les maths , ça m'intéresse" , I think.
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?
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.
Ah, merci pour cette explication.