Question

三分之二+三乘五分之二+五乘七分之二+七乘九分之二+九乘十一分之二+十一乘十三分之二=?简便计算

Answer 1

=1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13

=1-1/13

=12/13