脱式计算.
(1)75×80%+24×+0.8?????????????????
(2)
(3)(1.875-1÷)×
(4)(-)÷.
网友回答
解:(1)75×80%+24×+0.8,
=75×0.8+24×0.8+0.8,
=(75+24+1)×0.8,
=100×0.8,
=80;
(2)÷[×(-)],
=÷[×],
=÷,
=×,
=;
(3)(1.875-1÷)×,
=(-)×,
=0;
(4)(-)÷,
=(-)×24,
=×24,
=.
解析分析:(1)把百分数和分数化为小数,运用乘法分配律的逆运算简算;
(2)按运算顺序计算,先算小括号内的,再算中括号内的,最后算括号外的;
(3)通过计算,括号内的结果为0,因此得数为0;
(4)先算括号内的,再算括号外的.
点评:考查了四则混合运算,注意运算顺序,并灵活运用所学的运算定律简便计算.