You know what an x looks like, right? Among other things, it often signifies closing something; that’s why you see one in the upper right corners of a lot of computer windows. But x’s have another common use that’s incorrect! Incorrect of you know the trick, anyway.
Many houses are built at least partly out of 2×4 lumber, right? You said “two by four” when you read that, right?
I hate to tell you this, (Actually, I’m delighted to tell you this. It’s the whole point of this post.) but that’s not supposed to be an x between the 2 and the 4. It’s supposed to be a times sign! (Multiplication symbol if you want to be fancy.) This is a pretty common mistake. Even the guru of computer security, Bruce Schneier has made it at least once. I quote:
Tracking clients embed a line of code in the body of an email — usually in a 1×1 pixel image, so tiny it’s invisible, but also in elements like hyperlinks and custom fonts.
We have a pretty good excuse: They typical keyboard doesn’t have a key for the times sign. Herein lies your trick:
Hold down the Alt key and type 0215 on the numeric keypad. Release the Alt key. There’s your times sign!
Now you can have typographically correct lumber, dimensions, and equations. Go for it.