Sometimes you want to say "the new method is 18x faster" pronounced "eighteen times faster", how do you produce that cross in latex?
I tried
the new method is 18\times faster
But that italicises everything after it
What's the typesetting standard to use? To be honest, $\times$ doesn't look exactly right in the first place.

$starts or ends math mode. So if you have$\times, then you've started math mode, but not ended it. That will give you strange errors later on. gigair's answer shows how you would properly end math mode. – Teepeemm Mar 23 '21 at 17:56i didn't haveOh sorry, I see the confusion caused by the typo in the last sentence. I have never put$\times$\timesinto my document though. – minseong Mar 23 '21 at 17:5918\timesthere will be an error --- TeX will suggest to add a$because it's seeing a math-mode thing. If you run innonstopmodeyou will have the same effect as writing18$\times. Then TeX will add another$(with another error) at the end of the paragraph: this is why it "italicises everything after it" (in reality is math mode, not italics). So, never ignore errors... and better not run withnosnstopmode. – Rmano Mar 23 '21 at 18:08