1+2+3+...+24+25+326 +327+...+349+350=
5个回答

1+2+3+...+24+25+326 +327+...+349+350

=(1+25)x25÷2+(326+350)x25÷2

=13x25+338x25

=25x(13+338)

=25x351

=8775