Question 1157063
the sum of the arithmetic series below?
-100+-95+-90+-85+...+-5+0+5+...+85+90+95+100 is {{{0}}}

all negative:

{{{sum(5(n-21),n=0,20)=-1050}}}

all positive


{{{sum(5(n-21),n=0,20)=1050}}}


=>{{{-1050+1050=0}}}