怎样简便就怎样算.①400-(1300÷65+35) ②29+29×29 ③15×(41-17)÷30 ④19×96+9

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  • 解题思路:①先算小括号里面的除法,再算小括号里面的加法;

    ②运用乘法分配律简算;

    ③先算小括号里面的减法,再算括号外的乘法,最后算括号外的除法;

    ④同时运算乘法和除法,再算加法;

    ⑤先把44分解成4×11,再运用乘法分配律简算;

    ⑥运用加法结合律简算;

    ⑦运用乘法结合律简算;

    ⑧根据连续减去两个数,等于减去这两个数的和简算.

    ①400-(1300÷65+35),

    =400-(20+35),

    =400-55,

    =345;

    ②29+29×29,

    =(1+29)×29,

    =30×29,

    =870;

    ③15×(41-17)÷30,

    =15×24÷30,

    =360÷30,

    =12;

    ④19×96+962÷74,

    =1824+13,

    =1837;

    ⑤25×44,

    =25×(4×11),

    =25×4×11,

    =100×11,

    =1100;

    ⑥355+260+140+245,

    =(355+245)+(260+140),

    =600+400,

    =1000;

    ⑦50×25×20×40,

    =(50×20)×(25×40),

    =1000×1000,

    =1000000;

    ⑧645-180-245,

    =645-245-180,

    =400-180,

    =220.

    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进行简便计算.