I saw the sentence: 'We are starting class now' in a book of English grammar exercises.
But, I don't understand why the sentence has no article (the), like: 'We are starting the class now'.
I think this is simply an idiom, a less formal way of saying "We are starting the class now."
"We are starting class now." assumes that the people now which specific class ('the' definite article) is being described.
I think it is more commonly used in American english than UK english.