How to get approximation on one line?

Questions
1

I want to print out an approximation sign. I typed:

[ A N] $ approx $ [N A], but it prints everything out on 3 different lines, with the approx. sign in the middle of the page. How to get it all on one line so that it looks like this: [A N] = [N A] (with the approx sign instead of “=”?

2

The reason is because the equation is created as a block because of the spaces between the $s and approx. Removing them creates the equation inline:

[ A N] $approx$ [N A]

image

See the first example in the documentation:

The a, b, and c are inline equations. The remaining two are block-level.