解题思路:(1)运用加法交换律与结合律简算;
(2)把99看作100-1,运用乘法分配律简算;
(3)把125看作100+25,运用乘法分配律简算;
(4)(7)运用乘法分配律简算;
(5)把8看作2×4,运用乘法交换律与分配律简算;
(6)运用加法交换律与结合律简算.
(1)355+260+140+245,
=(355+245)+(260+140),
=600+400,
=1000;
(2)102×99,
=102×(100-1),
=10200-102,
=10200-100-2,
=10100-2,
=10098;
(3)2×125,
=2×(100+25),
=200+50,
=250;
(4)382×101-382,
=382×(101-1),
=382×100,
=38200;
(5)4×60×50×8,
=4×60×50×2×4,
=240×100×4,
=240×4×100,
=960×100,
=96000;
(6)645-180-245,
=(645-245)-180,
=400-180,
=220;
(7)35×8+35×6-4×35,
=35×(8+6-4),
=35×10,
=350.
点评:
本题考点: 运算定律与简便运算;整数、分数、小数、百分数四则混合运算.
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.