计算下面各题,怎样简便就怎样计算.

3个回答

  • 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.