Answer:
[tex]3 < n[/tex]
Step-by-step explanation:
We have the phrase "Three less than a number"
Three would be the number 3.
The phrase "less than" indicates a less than sign.
"A number" is unknown, so said number would be n. Of course, you can use any letter as your variable.
Three less than a number should be [tex]3 < n[/tex].