简便计算. ①111111÷1111×3333=_ ②6.25×0.16+2.64×0.0625+5.2×6.25=_ ③1/2-1/3+1/4-1/5+1/6-1/12=_.
问题描述:
简便计算.
①111111÷1111×3333=______
②6.25×0.16+2.64×0.0625+5.2×6.25=______
③
-1 2
+1 3
-1 4
+1 5
-1 6
=______. 1 12
答
①111111÷1111×3333,
=111111×3333÷1111,
=111111×(3333÷1111),
=111111×3,
=333333;
②6.25×0.16+264×0.0625+5.2×6.25,
=6.25×0.16+2.64×6.25+5.2×6.25,
=6.25×(0.16+2.64+5.2),
=6.25×8,
=(6+0.25)×8,
=48+2,
=50;
③
-1 2
+1 3
-1 4
+1 5
-1 6
,1 12
=(1-
)-1 2
+1 3
-1 4
+(1 5
-1 2
)-(1 3
-1 3
),1 4
=1-
+1 2
-(1 2
+1 3
+1 3
)+(1 3
+1 4
-1 4
),1 5
=
+1 4
-1 4
,1 5
=
-1 2
,1 5
=
.3 10
故答案为:333333,50,
.3 10