159824

If the bottom left hand corner was 4 then the number above it would be 9 nine. I know this because the bottom row is always the bottom left hand corner plus 1 like so 4,5,_,_. Then to find the second from the right on the bottom you would do the second from the left add 1 like so 4,5,6,_. To figure out the last number on the bottom you just add on 1 one to the second from the left and you would get the answer of 4,5,6,7. From there you can figure out the top one using the number pyramid.

bottom left hand corner =x
second from the left=w
second from the right=v
Bottom right hand corner=y

W=x+1
V=w+1
Y=v+1