(1) 1 3 + 2 5 + 2 15 = 11 15 + 2 15 = 13 15 答:种白菜、萝卜、芹菜的面积共占这块地的 13 15 .(2) 2 5 - 1 3 = 1 15 答:种白菜的面积比种萝卜的面积少 1 15 .