分析:(1)利用加法交換律與結(jié)合律簡算;
(2)(4)利用乘法分配律簡算;
(3)利用乘法交換律簡算;
(5)首先計(jì)算乘法和除法,再算減法;
(6)先算加法,再算除法,最后算乘法;
(7)先算除法,再算加法,最后算減法;
(8)先算小括號里面的減法,在算括號外面的減法.
解答:解:(1)1.29+3.7+0.71+6.3
=1.29+0.71+(6.3+3.7)
=2+10
=12;
(2)528×78+472×78
=(528+472)×78
=1000×78
=78000;
(3)125×89×8
=125×8×89
=1000×89
=89000;
(4)57×101-57
=57×(101-1)
=57×100
=5700;
(5)19×96-962÷74
=1824-13
=1811;
(6)(520+480)÷50×4
=1000÷50×4
=20×4
=80;
(7)400-(1300÷65+35)
=400-(20+35)
=400-55
=345;
(8)86.7-(14.3-3.8 )
=86.7-10.5
=76.2.
點(diǎn)評:混合運(yùn)算抓住運(yùn)算順序,同時注意數(shù)字和運(yùn)算符號特點(diǎn),靈活選用適當(dāng)?shù)姆椒ê瓦\(yùn)算定律簡算.