计算下面各题,后两题请用简便方法计算.2+0.45÷0.9-; ÷[×(-)];93+1.06++2.94;   3.78×6.2+3.78×3.8.

发布时间:2020-07-30 23:35:01

计算下面各题,后两题请用简便方法计算.
2+0.45÷0.9-; 
÷[×(-)];
93+1.06++2.94;   
3.78×6.2+3.78×3.8.

网友回答

解:(1)2+0.45÷0.9-;,
=2+0.5-0.875,
=1.625;

(2)÷[×(-)],
=÷[×],
=÷,
=×9,
=4;

(3)93+1.06++2.94,
=93+(1.06+0.07+2.94),
=93+4.07,
=97.07;

(4)3.78×6.2+3.78×3.8,
=3.78×(6.2+3.8),
=3.78×10,
=37.8.

解析分析:(1)把分数化为小数,先算除法,再算加减法;(2)先算小括号内的,再算中括号内的,最后算括号外的;(3)把分数化为小数,运用加法结合律先求出三个小数的和;(4)运用乘法分配律简算.

点评: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算.
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