题目内容
(1)3.875×(10.3-0.775)÷
(2)5.42-11.1÷[19.2×5.2-5.2×14.6+5.4×3.7-4.6×1.5].
解:(1)3.875×(10.3-0.775)÷,
=×(-)÷
=×××,
=(×)×(×),
=1×,
=;
(2)5.42-11.1÷[19.2×5.2-5.2×14.6+5.4×3.7-4.6×1.5],
=5.42-11.1÷[(19.2-14.6)×5.2-+5.4×3.7-4.6×1.5],
=5.42-11.1÷[4.6×5.2+5.4×3.7-4.6×1.5],
=5.42-11.1÷[4.6×(5.2-1.5)+5.4×3.7],
=5.42-11.1÷[4.6×3.7+5.4×3.7],
=5.42-11.1÷[(4.6+5.4)×3.7],
=5.42-11.1÷(10×3.7),
=5.42-11.1÷37,
=5.42-0.3,
=5.12.
分析:(1)先把小数化成分数,再算小括号里面的减法,然后运用乘法结合律简算;
(2)把中括号里面的计算多次运用乘法分配律简算,再算括号外的除法,最后算括号外减法.
点评:本题属于较复杂的运算,完成本题要注意分析式中数据,运用合适的简便方法计算.
=×(-)÷
=×××,
=(×)×(×),
=1×,
=;
(2)5.42-11.1÷[19.2×5.2-5.2×14.6+5.4×3.7-4.6×1.5],
=5.42-11.1÷[(19.2-14.6)×5.2-+5.4×3.7-4.6×1.5],
=5.42-11.1÷[4.6×5.2+5.4×3.7-4.6×1.5],
=5.42-11.1÷[4.6×(5.2-1.5)+5.4×3.7],
=5.42-11.1÷[4.6×3.7+5.4×3.7],
=5.42-11.1÷[(4.6+5.4)×3.7],
=5.42-11.1÷(10×3.7),
=5.42-11.1÷37,
=5.42-0.3,
=5.12.
分析:(1)先把小数化成分数,再算小括号里面的减法,然后运用乘法结合律简算;
(2)把中括号里面的计算多次运用乘法分配律简算,再算括号外的除法,最后算括号外减法.
点评:本题属于较复杂的运算,完成本题要注意分析式中数据,运用合适的简便方法计算.
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