解题思路:(1)先去括号,运用加法交换律与结合律简算;
(2)先算括号内的,再算括号外的;
(3)通分计算.
(1)[4/5]+([7/8]-[4/5]),
=[4/5]+[7/8]-[4/5],
=[4/5]-[4/5]+[7/8],
=[7/8];
(2)[7/10]-([2/15]+[1/6]),
=[7/10]-[3/10],
=[2/5];
(3)1-[1/3]-[1/7],
=1-[7/21]-[3/21],
=[11/21].
点评:
本题考点: 分数的四则混合运算.
考点点评: 此题考查了分数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.