(1/2+1/3+1/5)÷1/30+(1/3+1/5+1/7)÷1/105+(1/5+1/7+1/9)÷1/315=_.
问题描述:
(
+1 2
+1 3
)÷1 5
+(1 30
+1 3
+1 5
)÷1 7
+(1 105
+1 5
+1 7
)÷1 9
=______. 1 315
答
(12+13+15)÷130+(13+15+17)÷1105+(15+17+19)÷1315=(12+13+15)×30+(13+15+17)×105+(15+17+19)×315=15+10+6+35+21+15+63+45+35=(15+35+15+45+35)+(10+6+21+63)=145+100=245故答案为:245....