解题思路:(1)根据乘法分配律进行简算;
(2)根据乘法分配律进行简算;
(3)根据乘法结合律进行简算;
(4)根据乘法分配律进行简算.
(1)
4
7×23
12
13+
4
7×
1
13+16×
1
7
=
4
7×(23
12
13+
1
13)+4×4×
1
7
=
4
7×24+4×
4
7
=
4
7×(24+4)
=
4
7×28
=16;
(2)41.2×3.6+16×1
1
4+53.7×6.4
=41.2×3.6+20+53.7×6.4
=41.2×(10-6.4)+20+53.7×6.4
=41.2×10-41.2×6.4+20+53.7×6.4
=412+20+53.7×6.4-41.2×6.4
=432+(53.7-41.2)×6.4
=432+12.5×8×0.8
=432+80
=512;
(3)0.78÷2.6×1.8÷0.12
=(0.78÷2.6)×(1.8÷0.12)
=0.3×15
=4.5;
(4)12.6×125%+3
2
5÷
4
5
=12.6×1.25+3
2
5×1.25
=(12.6+3
2
5)×1.25
=16×1.25
=1×(8×1.25)
=20.
点评:
本题考点: 运算定律与简便运算.
考点点评: 完成本题要注意分析式中数据,运用合适的简便方法计算.