I need to find the volume of region bound by z = x + y z = 10 and the planes x= 0 and y = 0

I set up an integral from 0 to 10 then from 0 to 10 - x and from 10 to x + y dzdydx with the function being one dzdydx

I get an answer 5 times the amount I should. Could someone please tell me if I miscalculated the bounds on one of my integrals??? Thanks so much for the assistance, Frostking