解题思路:(1)(5)(6)依据四则运算计算方法,先算第二级运算,再算第一级运算,如果只含有同一级运算,按照从左到右书序计算,有括号先算括号里面的解答,
(2)(3)(4)运用乘法分配律解答.
(1)[5/7]÷(5-3×[2/3]),
=[5/7]÷(5-2),
=[5/7]÷3,
=[5/21];
(2)85×[1/4]+0.25×15,
=0.25×(85+15),
=0.85×100,
=85;
(3)24×([2/3−
1
2+
1
4]),
=24×[2/3]-24×[1/2]+24×[1/4],
=16-12+6,
=4+6,
=10;
(4)5.9×101,
=5.9×(100+1),
=5.9×100+5.9×1,
=590+5.9,
=595.9;
(5)[1/2]÷[([2/3−
2
5])×[7/10]],
=1[1/2]÷[[4/15×
7
10]],
=[1/2]÷
14
75,
=2[19/28];
(6)(1-[1/4]-[5/12])÷
2
3,
=([3/4−
5
12])÷
2
3,
=[1/3]÷
2
3,
=0.5.
点评:
本题考点: 分数的四则混合运算;分数的简便计算;整数、分数、小数、百分数四则混合运算.
考点点评: 本题主要考察学生运用四则运算计算方法,以及正确运用乘法分配律的能力.