(m+3m+5m+7m+.+2009m)-(2m-4m-6m-.-2008m)=?

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(m+3m+5m+7m+.+2009m)-(2m-4m-6m-.-2008m)=?

(m+3m+5m+7m+.+2009m)-(2m-4m-6m-.-2008m)=?
(m+3m+5m+7m+.+2009m)-(2m-4m-6m-.-2008m)=?

(m+3m+5m+7m+.+2009m)-(2m-4m-6m-.-2008m)=?
(m+3m+5m+7m+.+2009m)-(2m+4m+6m+.+2008m)
=(1+3+5+7+.+2009)m-(2+4+6+.+2008)m
=【(1+2009)×1005÷2-(2+2008)×1004÷2】×m
=【2010×1005÷2-2010×1004÷2】×m
=1005m

原题有错误,后面括号内应全部为加号
原式=(1+3+5+...+2009)m-(2+4+6+...+2008)m
=(1-2+3-4+5-6+...-2008+2009)m
=[1+(3-2)+(6-5)+...+(2009-2008)]m
=[1×(2009-1)÷2]m
=1004m

原式=(2009m-2008m)+(2007m-2006m)+(2005m-2004m)+……+(7m-6m)+(5m-4m)+(3m-2m)+m
=m+m+m+m++……+m
=1005m