解题思路:(1)根据连减的性质进行计算;
(2)先算加法,再算乘法,最后算除法;
(3)先算减法,再算乘法,再算加法,最后算乘法;
(4)根据乘法分配律进行计算;
(5)先算除法,再算加法;
(6)先算除法,再根据连减的性质进行计算.
(1)22.3-2.45-5.3-4.55,
=(22.3-5.3)-(2.45+4.55),
=17-7,
=10;
(2)[9/20÷[
1
2×(
2
5+
1
3)],
=
9
20]÷[[1/2]×[11/15]],
=[9/20]÷[11/30],
=[27/22];
(3)[43.3×(2-75%)+7]×[1/2],
=[43.3×1.25+7]×[1/2],
=[54.125+7]×[1/2],
=61.125×[1/2],
=30.5625;
(4)[9/20×103−
9
20×3,
=
9
20×(103−3),
=
9
20×100,
=45;
(5)
5
9÷5+
4
9÷4,
=
1
9]+[1/9],
=[2/9];
(6)12−
6
13÷
9
26−
2
3,
=12-[4/3]-[2/3],
=12-([4/3]+[2/3]),
=12-2,
=10.
点评:
本题考点: 小数四则混合运算;运算定律与简便运算;分数的四则混合运算.
考点点评: 此题主要考查分数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.