1+2-3+4-5+…-99+100=_.

问题描述:

1+2-3+4-5+…-99+100=______.

1+2-3+4-5+…-99+100,
=1-[(3-2)+(5-4)+…+(99-98)]+100,
=1-[1×49]+100,
=1-49+100,
=52;
故答案为:52.