解题思路:(1)先算除法,再算加法和减法;
(2)把小数化为分数,再计算;
(3)运用加法交换律与结合律简算;
(4)把64看作4×2×8,把百分数化为小数,运用乘法交换律与结合律简算;
(5)先算小括号内的,再算中括号内的,最后算括号外的;
(6)把百分数和和分数化为小数,运用乘法分配律简算.
(1)1020+270÷18-864,
=1020+15-864,
=171;
(2)[2/3÷0.8×
3
4],
=[2/3]÷[4/5]×[3/4],
=[2/3]×[5/4]×[3/4],
=[5/8];
(3)[1/8]+[5/7]+6.875+[2/7],
=([1/8]+6.875)+([5/7]+[2/7]),
=(0.125+6.875)+1,
=7+1,
=8;
(4)0.25×64×125%,
=0.25×4×2×8×1.25,
=(0.25×4)×(8×1.25)×2,
=1×10×1,
=20;
(5)[[8/15]-([7/12]-[2/5])]×[15/14],
=[[8/15]-[11/60]]×[15/14],
=[21/60]×[15/14],
=[3/8];
(6)6.35×0.75+4.65×75%-[3/4],
=6.35×0.75+4.65×0.75-0.75,
=(6.35+4.65-1)×0.75,
=10×0.75,
=7.5.
点评:
本题考点: 整数、分数、小数、百分数四则混合运算;整数四则混合运算.
考点点评: 此题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定律简便计算.