计算,(能简算的要简算) 336÷[7×(36÷9)]99×999+99948×12520×7×5×3600÷30+20×6(30×24-26)÷70.
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解:(1)336÷[7×(36÷9)],
=336÷[7×4],
=336÷28,
=12;
(2)99×999+999,
=(99+1)×999,
=100×999,
=99900;
(3)48×125,
=(6×8)×125,
=6×(8×125),
=6×1000,
=6000;
(4)20×7×5×3,
=(20×5)×(7×3),
=100×21,
=2100;
(5)600÷30+20×6,
=20+120,
=140;
(6)(30×24-26)÷70,
=(720-26)÷70,
=694÷70,
=.
解析分析:(1)先算小括号里面的除法,再算中括号里面的乘法,最后算括号外的除法;
(2)运用乘法分配律简算;
(3)先把48分解成6×8,再运用乘法结合律简算;
(4)运用乘法交换律和结合律简算;
(5)先同时运算除法和乘法,再算加法;
(6)先算小括号里面的乘法,再算小括号里面的减法,最后算括号外的除法.
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.