Which of the following is an example of the Associative Property?
(13 + 20) = (20 + 13)
(13 + 20) + 15 = 13+ (20 + 15)
(13 + 20) + 15 = 15+ (13 + 20)
(13 * 20 * 15 = 13 * (20 * 15)
Someone please help!