Is it "la clase de matemáticas es divertida." or do you have to add an s divertida because of matemáticas? explain.

No you just have to leave it there, is " La clase de matemáticas es divertida" Hope this can help you! From: Ecuador

It's "la clase de matemáticas es divertida" with no s. Because math is not a plural word so you don't add the s. Another reason why there can't be an s is because if it was plural. The sentence would have the word "son" instead of "es". "Son" means are.

I'm Colombian but was raised in an English speaking country so I speak both Spanish and English.

Los tenis mean the shoes