计算:(78.6-0.786×25+75%×21.4)÷15×2009=________.
网友回答
10045
解析分析:先把小括号里面的运算两次运用乘法分配律简算,再算括号外的除法,最后算括号外的乘法.
解答:(78.6-0.786×25+75%×21.4)÷15×2009,
=(78.6×1-78.6×0.25+0.75×21.4)÷15×2009,
=[78.6×(1-0.25)+0.75×21.4]÷15×2009,
=[78.6×0.75+0.75×21.4]÷15×2009,
=[0.75×(78.6+21.4)]÷15×2009,
=[0.75×100]÷15×2009,
=75÷15×2009,
=5×2009,
=10045.
故