100+99-98-97+96+95+·······+4+3-2-1怎么做?

问题描述:

100+99-98-97+96+95+·······+4+3-2-1怎么做?

=(100+99-98-97)……(4+3-2-1)
=4+……+4
=4*(100/4)
=4*25
=100