简便计算. +3.6+ +6.6 | 3.4- - | 2.5×32×12.5 |
| 3.4×5.6+5.6×6.6 | 10.2×43. |
+3.6+
+6.6,=(
+
)+(3.6+6.6),=1+10,
=11;
(2)3.4-
-
,=3.4-(
+
),=3.4-1,
=2.4;
(3)2.5×32×12.5,
=2.5×4×8×12.5,
=(2.5×4)×(8×12.5),
=10×100,
=1000;
(4)3.4×5.6+5.6×6.6,
=(3.4+6.6)×5.6,
=10×5.6,
=56;
(5)10.2×43,
=(10+0.2)×43,
=430+8.6,
=438.6.
分析:(1)运用加法交换律与结合律简算;
(2)运用减法的性质简算;
(3)把32看作4×8,运用乘法结合律简算;
(4)运用乘法分配律简算;
(5)把10.2看作10+0.2,运用乘法分配律简算.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.