(5/14+1/25)×9+16/25简便方法(5/14+1/25)×9+16/25=5/14×9+1/25×9+16/25=45/14+9/25+16/25=3又3/14+（9/25+16/25）=3又3/14+1=4又3/14
乘法分配律
