Question

How do you write three times a number w is less than 18

Answer 1

3xA>18
Three times A is less than 18
A is the variable

Answer 2

Three times a number (w) is less than 18.
I would personally write it 3w<18.
You may be looking for 3 x w-18 or 3w-18 or possibly 3*w-18