My English is excellent, but I'd like to know whether this is grammatically correct, especially in a formal situation. My slang/day-to-day English is excellent, but I don't know if this would be grammatically correct for writing a novel or a formal e-mail.
Would it be grammatically correct to say, for example:
"He is older than me by one year."
"He is one year older than me."
Are both correct, grammatically?