解题思路:(1)先算乘法,再算加法;
(2)根据减法的性质以及加法结合律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法交换律和结合律进行计算;
(5)先算加法,再算除法;
(6)先算除法,再算乘法,最后算加法.
(1)[7/8+
1
8×
8
9],
=[7/8]+[1/9],
=[71/72];
(2)0.577-(0.477−
11
13)+
2
13,
=0.577-0.477+[11/13]+[2/13],
=(0.577-0.477)+([11/13]+[2/13]),
=0.1+1,
=1.1;
(3)(
5
9+
4
7)×9×7,
=[5/9]×9×7+[4/7]×9×7,
=35+36,
=71;
(4)(
3
11×
2
13)×11×13,
=([3/11]×11)×([2/13]×13),
=3×2,
=6;
(5)69÷(69+
69
70),
=69÷69[69/70],
=[70/71];
(6)18+8÷9×
1
9,
=18+[8/9]×[1/9],
=18+[8/81],
=18[8/81].
点评:
本题考点: 分数的四则混合运算;运算定律与简便运算.
考点点评: 此题主要考查分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.