I need help whats this answer

Can someone answer it, and plot it, for 20 points and brainliest answer? p.s. they're the same ! : )

James adds two numbers a + b. sally adds the same two numbers but reverse the order b + a what property of addition assures us that james and sally will get the same sum

Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of triangle abc is 180