考点:小数四则混合运算,运算定律与简便运算
专题:运算顺序及法则,运算定律及简算
分析:(1)运用加法的交换律进行简算;
(2)运用减法的性质进行简算;
(3)运用乘法的分配律进行简算;
(4)运用除法的性质进行简算;
(5)把32化成8×4,再运用乘法的交换律、结合律进行简算;
(6)运用除法的性质进行简算;
(7)把201化成200+1,再运用乘法的分配律进行简算.
解答:
解:(1)4.9+4.57+5.1
=4.9+5.1+4.57
=10+4.57
=14.57;
(2)18.3-5.7-3.3
=18.3-(5.7+3.3)
=18.3-9
=9.3;
(3)4.8×18.4+4.8×1.6
=4.8×(18.4+1.6)
=4.8×20
=96;
(4)12.76÷0.4÷2.5
=12.76÷(0.4×2.5)
=12.76÷1
=12.76;
(5)0.25×1.25×32
=0.25×1.25×8×4
=0.25×4×1.25×8
=(0.25×4)×(1.25×8)
=1×10
=10;
(6)(7.7+1.54)÷7
=7.7÷7+1.54÷7
=1.1+0.22
=1.32;
(7)0.24×201
=0.24×(200+1)
=0.24×200+0.24×1
=48+0.24
=48.24.
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.