计算题9l,a(I7I1E8?
7×75－7×259l,a(I7I1E8?
算式：提示2J6|;l3^)K.@6S8f.V)j,V0^*Y7u4_8B9l,a(I7I1E8?
＝2[,V+M:y;]9l,a(I7I1E8?