怎样简便就怎样计算. 49×102-2×49125×76×8833-243-45799×3267+263+4341000÷(41×5)5824÷8×(85-78)840÷28+70×18.
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解:(1)49×102-2×49,
=49×(102-2),
=49×100,
=4900;
(2)125×76×8,
=125×8×76,
=1000×76,
=76000;
(3)833-243-457,
=833-(243+457),
=833-700,
=133;
(4)99×32,
=(100-1)×32,
=100×32-1×32,
=3200-32,
=3168;
(5)67+263+43,
=67+43+263,
=110+263,
=373;
(6)41000÷(41×5),
=41000÷41÷5,
=1000÷5,
=200;
(7)5824÷8×(85-78),
=5824÷8×7,
=728×7,
=5096;
(8)840÷28+70×18,
=30+1260,
=1290.
解析分析:(1)(4)运用乘法分配律简算;
(2)运用乘法交换律简算;
(3)根据减法的性质简算;
(5)运用加法交换律简算;
(6)根据除法的性质简算;
(7)先算小括号里面的减法,再算除法,最后算乘法;
(8)先同时运算除法和乘法,再算加法.
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.