解题思路:(1)依据减法的性质化原式为:4.67-2.98-0.67,再依据加法的结合律解答,
(2)依据减法性质解答,
(3)运用乘法交换律和结合律解答,
(4)(5)(6)运用乘法分配律解答.
(1)4.67-(2.98+0.67),
=4.67-0.67-2.98,
=4-2.98,
=1.02;
(2)[8/49]÷[[9/8]-([1/8]+[3/7])],
=[8/49]÷[[9/8]−
1
8−
3
7],
=[8/49]÷[1-[3/7]]
=[8/49]÷[4/7],
=[2/7];
(3)8×0.4×12.5×2.5,
=(8×12.5)×(0.4×2.5),
=100×1,
=100;
(4)125×(8+0.8+0.08),
=125×8+125×0.8+125×0.08,
=1000+100+10,
=1110;
(5)1.89×0.9+0.189,
=1.89×0.9+1.89×0.1,
=1.89×(0.9+0.1),
=1.89×1,
=1.89;
(6)23.8×99+2.38,
=23.8×(100-1)+2.38,
=23.8×100-23.8×1+2.38,
=2380-23.8+2.38,
=2356.2+2.38,
=2358.58.
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: 本题主要考查学生运用四则运算计算,以及运用定律和性质简算的能力.