急0.72*0.58+0.28*0.38=?简便计算_数学解答

急0.72*0.58+0.28*0.38=?简便计算

人气：401 ℃　时间：2020-02-03 13:18:34

解答

0.72*0.58+0.28*0.38
=(1-0.28)*0.58+0.28*0.38
=0.58-0.28*0.58+0.28*0.38
=0.58-0.28*(0.58-0.38)
=0.58-0.28*0.2
=0.58-0.056
=0.524