题目内容
直接写出得数. 0.44+++0.6 | +2×2-2÷ | (4-2)÷(1+2.4) |
48200-156×720÷39 | (3.06÷0.25+2.76)×0.2 | [3÷(3-2.4×)]×0.2. |
解:(1)0.44+++0.6,
=0.44+0.4+0.56+0.6,
=(0.44+0.56)+(0.4+0.6),
=1+1,
=2;
(2)+2×2-2÷,
=+-3,
=5-3,
=2;
(3)(4-2)÷(1+2.4),
=2÷3,
=×,
=;
(4)48200-156×720÷39,
=48200-112320÷39,
=48200-2880,
=45320;
(5)(3.06÷0.25+2.76)×0.2,
=(12.24+2.76)×0.2,
=15×0.2,
=3;
(6)[3÷(3-2.4×)]×0.2,
=[3÷(3-)]×0.2,
=[3÷]×0.2,
=×,
=.
分析:(1)先把分数化成小数,然后再运用加法结合律简算;
(2)同时运算乘法和除法,再算加法,最后算减法;
(3)同时运算两个小括号里面的减法和加法,最后算括号外的除法;
(4)先算乘法,再算除法,最后算减法;
(5)先算小括号里面的除法,再算小括号里面的加法,最后算括号外的乘法;
(6)先算小括号里面的乘法,再算小括号里面的减法,然后算中括号里面的除法,最后算括号外的乘法.
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.
=0.44+0.4+0.56+0.6,
=(0.44+0.56)+(0.4+0.6),
=1+1,
=2;
(2)+2×2-2÷,
=+-3,
=5-3,
=2;
(3)(4-2)÷(1+2.4),
=2÷3,
=×,
=;
(4)48200-156×720÷39,
=48200-112320÷39,
=48200-2880,
=45320;
(5)(3.06÷0.25+2.76)×0.2,
=(12.24+2.76)×0.2,
=15×0.2,
=3;
(6)[3÷(3-2.4×)]×0.2,
=[3÷(3-)]×0.2,
=[3÷]×0.2,
=×,
=.
分析:(1)先把分数化成小数,然后再运用加法结合律简算;
(2)同时运算乘法和除法,再算加法,最后算减法;
(3)同时运算两个小括号里面的减法和加法,最后算括号外的除法;
(4)先算乘法,再算除法,最后算减法;
(5)先算小括号里面的除法,再算小括号里面的加法,最后算括号外的乘法;
(6)先算小括号里面的乘法,再算小括号里面的减法,然后算中括号里面的除法,最后算括号外的乘法.
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.
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