用简单方法计算下面各题，是小学生的，小学教师都不会，请网友回答

Question

1997*0.3/1999*0.5+1.2/1999

Answer 1

（1997+2）-2*3/10=(1999*3/10-6/10)
(1999*3/10-6/10)*(2/1999)=6/10-6/10*2/1999=6/10(1-2/1999)
6/10(1-2/1999)+6/5/1999=6/10+0=3/5+0=3/5

Answer 2

1997*0.3/1999*0.5+1.2/1999
=1997*0.3/1999*0.5+2*.03/1999*0.5
=(1997+2)*0.3/1999*0.5
=1999*0.3/1999*0.5
=0.3/0.5
=3/5

Answer 3

＝（1999-2）*0.3/(1999*0.5)+1.2/1999=0.3/0.5-0.6/(1999*0.5)+1.2/1999=3/5-1.2/1999+1.2/1999=0.6