解题思路:①运用加法交换律和结合律简算;
②把分数[7/20]化为小数0.35,然后把0.35×6改写成0.35×4+0.35×2,运用乘法分配律简算.
①[1/5]-[3/7]+[6/5]-[4/7],
=([1/5]+[6/5])-([3/7]+[4/7]),
=[7/5]-1,
=[2/5];
②2.65×4+[7/20]×6,
=2.65×4+0.35×6,
=2.65×4+0.35×4+0.35×2,
=(2.65+0.35)×4+0.7,
=3×4+0.7,
=12+0.7,
=12.7.
点评:
本题考点: 分数的简便计算.
考点点评: 此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.