解题思路:四则运算的计算顺序是:先算二级运算,再算一级运算,有括号的要先算括号里面的.
(1)(2)(3)可根据减法的性质进行计算,
(4)根据加法交换律和减法的性质进行计算,
(5)(6)根据加法交换律和结合律进行计算.
(1)7827-(827+1200),
=7827-827-1200,
=7000-1200,
=5800;
(2)576-285+85,
=576-(285-85),
=576-200,
=376;
(3)643-167-133-243,
=643-243-(167+133),
=643-243-300,
=100;
(4)748-351+252-149,
=748+252-(351+149),
=748+252-500,
=1000-500,
=500;
(5)1028+54+340+106,
=1028+340+(54+106),
=1028+(340+160),
=1028+500,
=1528;
(6)38+62-38+62,
=38-38+62+62,
=62+62,
=124.
点评:
本题考点: 整数四则混合运算;运算定律与简便运算.
考点点评: 本题主要考查了学生在四则运算中灵活运用简便算法的计算能力.