计算.
[-÷(4.9-3.4)]×
6×+0.75×2
×[+(-0.25)]
÷+÷.
网友回答
解:(1)[-÷(4.9-3.4)]×
=[-÷1.5]×
=[-÷]×
=[-×]×
=×[1-]×
=××
=;
(2)6×+0.75×2
=6×+×2
=(6+2)×
=8×
=6;
(3)×[+(-0.25)]
=×[+(-)]
=×
=;
(4)÷+÷
=×+×
=(+)×
=1×
=.
解析分析:(1)先算小括号内的,再算中括号内的除法,然后算中括号内的减法,最后算括号外的乘法;
(2)把小数化为分数,运用乘法分配律简算;
(3)把小数化为分数,小括号内的结果为0,再算×即可;
(4)把除法改为乘法,运用乘法分配律简算.
点评:考查了运算定律与简便运算,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律简便计算.