The sixth grade students went on a spring outing and bought some apples and pears. I bought 180 apples, which is 12 less than three times that of Sydney. How many pears did you buy? (solution by equation)
六年级同学春游，买了一些苹果和雪梨．买来苹果180个，比雪梨的3倍少12个．买了雪梨多少个？(用方程解)
<result>63</result>