计算: ①18.3×0.25+5.3÷0.4-7.13=_;   ②1/20043−2003×(20042+2005)=_.

问题描述:

计算:
①18.3×0.25+5.3÷0.4-7.13=______;  

1
20043−2003×(20042+2005)
=______.

①18.3×0.25+5.3÷0.4-7.13
=4.575+13.25-7.13
=17.825-7.13
=10.695;

1
20043−2003×(20042+2005)

=
1
20042×2004−2003×20042−2003×2005

=
1
20042×(2004−2003)−2003×2005

=
1
20042−2003×2005

=
1
20042−2003×(2004+1)

=
1
20042−2003×2004−2003

=
1
2004×(2004−2003)−2003

=
1
2004−2003

=1.
故答案为:10.695,1.