解题思路:(1)先算乘法和除法,再算减法;
(2)先算乘法,再利用结合律简算;
(3)先算除法,再算减法,最后算乘法;
(4)利用乘法分配律简算;
(5)利用加法交换律与减法的性质简算;
(6)先算减法,再算括号里面的除法,再算括号外面的除法.
(1)68×35-408÷24
=2380-17
=2363;
(2)[5/7]+[9/8]×[7/9]+[1/8]
=[5/7]+([7/8]+[1/8])
=[5/7]+1
=1[5/7];
(3)(0.63-0.63÷3)×0.5
=(0.63-0.21)×0.5
=0.42×0.5
=0.21;
(4)3.64×0.25+4.36×0.25
=(3.64+4.36)×0.25
=8×0.25
=2;
(5)1.3-3.79+9.7-6.21
=1.3+9.7-(3.79+6.21)
=11-10
=1;
(6)[3/22]÷[[5/4]÷([14/3]-[1/2])]
=[3/22]÷[[5/4]×[6/25]]
=[3/22]×[10/3]
=[5/11].
点评:
本题考点: 整数四则混合运算;分数的四则混合运算.
考点点评: 混合运算的关键是抓住运算顺序,正确按运算顺序计算即可.