Nora, the distributive property is the opposite of the P in PEMDAS. Normally, if we want to do 3(7 + 5), we would do 3(12) = 36, but we can also do 3(7) + 3(5) = 21 + 15 = 36.
509 = 500 + 9, right? To simplify multiplying by 11, break it up and multiply each part by 11. It'll look like 500(11) + 9(11).
Hope this helps!
