Question

Tính nhanh tổng:

1/2:3+1/3:4+...1/2016:2017

Answer 1

=1/2 - 1/3 +1/3 - 1/4 +...+1/2016 - 1/2017
=1/2 - 1/2017
=...

Answer 2

1/2:3+1/3:4+1/4:5+...1/2016:2017

1/2.1/3+1/3.1/4+1/4.1/5+...1/2016.1/2017

1/2.3+1/3.4+1/4.5+...1/2016.2017

1/2-1/3+1/3-1/4+1/4-1/5+...1/2016-1/2017

=1/2-1/2017

=2017/4034-2/4034

=2015/4034