What is this just tell me what the l and w ='s

You didn't show us much of the page with the question on it,
so we can't be sure of exactly what you're working on in math.

If you're working with things like squares and rectangles, then
'L' and 'W' are often used to represent the Length and Width of
shapes drawn on paper, or even Length and Width of 3D objects
like blocks or boxes. 

L= length
W= width
hope this helps!