Question

1/2+5/6+11/12+19/20+……+109/110（简便运算）怎么算?请各位快回答,

Answer 1

1/2+5/6+11/12+19/20+……+89/90+109/110

=1-1/2+1-1/6+1-1/12...+1-1/110

=10-(1/2+1/6+1/12...+1/110)

=10-(1/2+1/2-1/3+1/3-1/4+1/5-1/5...+1/10-1/11)

=10-10/11

=100/11