解题思路:(1)运用乘法交换律与结合律简算;
(2)两个括号同时计算,最后算乘法;
(3)运用乘法分配律简算;
(4)先算小括号内的,再算中括号内的,最后算括号外的.
(1)12.5×38×0.8,
=(12.5×0.8)×38,
=10×38,
=380;
(2)(8.5-4)×(0.32÷1.6),
=4.5×0.2,
=0.9;
(3)6.5×4.6+6.5×15.4,
=6.5×(4.6+15.4),
=6.5×20,
=130;
(4)[9/8]÷[[3/4]÷(1-[1/8])],
=[9/8]÷[[3/4]÷[7/8]],
=[9/8]÷[[3/4]×[8/7]],
=[9/8]÷[6/7],
=[9/8]×[7/6],
=[21/16].
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: 此题考查了小树和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.