海淀区游泳健身馆:Help me , please! 0.7*56+0.3*55=?

来源:百度文库 编辑:杭州交通信息网 时间:2024/05/05 00:07:44
求求各位,小妹这个作业明儿就得交了,帮帮我吧!

0.7*56+0.3*55
=0.7*(55+1)+0.3*55
=0.7*55+0.7*1+0.3*55
=0.7*55+0.3*55+0.7
=55*(0.7+0.3)+0.7
=55*1+0.7
=55.7

这是简便运算的方法。

直接算:
0.7*56+0.3*55
=39.2+16.5
=55.7

0.7*56+0.3*55
=39.2+16.5
=55.7

=39.2+16.5
=55.7

55.7