递等式计算下面各题.72-44+85 234-135÷9 144+(57-12)×2 95-15×6+41 (15+20

1个回答

  • 解题思路:(1)按照从左到右的顺序计算;

    (2)先算除法,再算减法;

    (3)先算减法,再算乘法,最后算加法;

    (4)先算乘法,再算减法,最后算加法;

    (5)先算小括号里面的加法,再算括号外的乘法;

    (6)先同时运算两个小括号里面的加法和减法,再算除法.

    (1)72-44+85,

    =28+85,

    =113;

    (2)234-135÷9,

    =234-15,

    =219;

    (3)144+(57-12)×2,

    =144+45×2,

    =144+90,

    =234;

    (4)95-15×6+41,

    =95-90+41,

    =5+41,

    =46;

    (5)(15+20)×3,

    =35×3,

    =105;

    (6)(75+30)÷(20-5),

    =105÷15,

    =7.

    点评:

    本题考点: 整数四则混合运算.

    考点点评: 本题关键是理清楚运算的顺序,找出先算什么,再算什么,根据运算的顺序逐步求解即可.