解题思路:(1)运用加法交换律与结合律简算;
(2)把除法改为乘法,运用乘法分配律简算;
(3)先算括号内的乘法,再算括号内的减法,最后算括号外的除法;
(4)运用乘法分配律简算,同时把分数化为小数;
(5)先算除法,再算加法.
(1)7.28+[3/7]+2.72+[4/7],
=(7.28+2.72)+([3/7]+[4/7]),
=10+1,
=11;
(2)([3/8]+[1/6])÷[1/24],
=([3/8]+[1/6])×24,
=[3/8]×24+[1/6]×24,
=9+4,
=13;
(4)168.1÷(4.3×2-0.4),
=168.1÷(8.6-0.4),
=168.1÷8.2,
=20.5;
(5)36×[5/8]+36×0.375,
=36×([5/8]+0.375),
=36×(0.625+0.375),
=36×1,
=36;
(6)[3/7]+[6/7]÷[2/3],
=[3/7]+[6/7]×[3/2],
=[3/7]+[9/7],
=[12/7].
点评:
本题考点: 运算定律与简便运算;整数、分数、小数、百分数四则混合运算.
考点点评: 考查了四则混合运算,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.