1+2+3+4+5+6+7+8+9+10+11+12+13+141+56+789-888=
3个回答

1+2+3+4+5+6+7+8+9+10+11+12+13+141+56+789-888

=(1+13)*13/2+141+56+789-888

=91+141+56+789-888

=880-888+141+56

=189