计算:(1/2+1/4+1/6+1/8)−(1/3+1/6+1/9+1/12)+(1/4+1/8+1/12+1/16)−(1/5+1/10+1/15+1/20)=_.
问题描述:
计算:(
+1 2
+1 4
+1 6
)−(1 8
+1 3
+1 6
+1 9
)+(1 12
+1 4
+1 8
+1 12
)−(1 16
+1 5
+1 10
+1 15
)=______. 1 20
答
(12+24+18+116)-(13+16+19+112)+(14+18+112+116)+(15+110+115+120)=12×(1+12+13+14)−13×(1+12+13+14)+14×(1+12+13+14)−15×(1+12+13+14),=(1+12+13+14)×(12−13+14−15),=2512×1360,=65144....