(2013•东莞模拟)正确、合理、灵活的计算下面各题.
1个回答

解题思路:算式①③④⑤⑥都是运用乘法的分配律进行计算,使计算更加简便.

算式②运用一个数减去两个数的差,可以用这个数减去被减数加上减数.

①(1.75×0.2+1.75×0.8)÷0.175,

=1.75×(0.2+0.8)÷0.175,

=1.75÷0.175,

=10;

②10[1/4]-(6[1/4]-2[1/5]),

=10.25-6.25+2.2,

=4+2.2,

=6.2;

③243×8[1/4]+75.7×82.5,

=243×8.25+757×8.25,

=8.25×(243+757),

=8.25×1000,

=8250;

④[3/8]×1[1/4]+125%+0.625×1.25,

=0.375×1.25++1.25+0.625×1.25,

=1.25×(0.375+0.625+1),

=1.25×2,

=2.5;

⑤0.91÷[4/5]+1.25×1.09,

=0.91×1.25+1.25×1.09,

=1.25×(0.91+1.09),

=1.25×2,

=2.5;

⑥([5/6]+[7/8]-[5/12])÷[1/24],

=([5/6+

7

8−

5

12])×24,

=24×[5/6]+24×[7/8]-24×[5/12],

=20+21-10,

=31.

点评:

本题考点: 整数、分数、小数、百分数四则混合运算.

考点点评: 本题主要考查了学生能否根据数字的特点,选择运用乘法的分配律进行计算,运用运算定律使计算更加简便.