(1)360+24÷15×30???????????????????
(2)0.25×7.2+2.8÷0.5
(3)×29-8×
(4)(+-)÷.
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解:(1)360+24÷15×30,
=360+×30,
=360+48,
=408;
(2)0.25×7.2+2.8÷0.5,
=1.8+5.6,
=7.4;
(3)×29-8×,
=×(29-8),
=×21,
=9;
(4)(+-)÷,
=(+-)×24,
=×24+×24-×24,
=20+21-10,
=41-10,
=31.
解析分析:(1)先算除法,再算乘法,最后算加法;
(2)同时运算乘法和除法,最后算加法;
(3)运用乘法分配律简算;
(4)先把除法变成乘法,再运用乘法分配律简算.
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.