(1+3+5+······+99+101)—(2+4+6······+98+100)
=1+3+5+······+99+101-2-4-6-······-98-100
=(1-2)+(3-4)+(5-6)+……+(99-100)+101
=(-1)+(-1)+(-1)+……+(-1)+101 [共有50个(-1)相加]
=(-1)×50+101
=-50+101
=51
(1+3+5+······+99+101)—(2+4+6······+98+100)
=1+3+5+······+99+101-2-4-6-······-98-100
=(1-2)+(3-4)+(5-6)+……+(99-100)+101
=(-1)+(-1)+(-1)+……+(-1)+101 [共有50个(-1)相加]
=(-1)×50+101
=-50+101
=51