#3n<52# would be "three multiplied by a number is less than fifty-two".
Explanation:
Let's refer to #n# as "a number." It represents some number whose value we don't quite know, so referring to it as "a number" is the best we can really do.
#3n# would then be three multiplied by a number .
#<# represents "less than."
So, #3n<52# would be "three multiplied by a number is less than fifty-two".