Maths is / Maths are
In British English, maths is written with an S whereas in American English it's written math without S.

In British English, what should I write ?
"Maths is everywhere" or "Maths are everywhere" ?
"When your maths is done, do your French." or "When your maths are done, do your French."

Same question in American English :
"Math is everywhere" or "Math are everywhere" ?
"When your math is done, do your French." or "When your math are done, do your French."

Question

Maths is / Maths are
In British English, maths is written with an S whereas in American English it's written math without S.

In British English, what should I write ?
"Maths is everywhere" or "Maths are everywhere" ?
"When your maths is done, do your French." or "When your maths are done, do your French."

Same question in American English :
"Math is everywhere" or "Math are everywhere" ?
"When your math is done, do your French." or "When your math are done, do your French."

Answer

Maths / Math = Mathematics, and it is a subject) Its form is Singular, same as Phonetics, for instance, as far as I remember) That is why when you say "maths" or "math" you should put "is", not "are" :)

Answer

In American English math is singular, so, "when when your math is done..."
I think, though I am not sure, that in British English "maths" should be treated as plural.  I'm interested in hearing what our UK friends have to say about this.

Answer

There's no plural for any subject u study even though they are singular & find s in the endings like maths, physics, civics, economics. So always to be used as "is".
 Eg; Maths is too hard to understand the formula.