(+22\7)*(22\7-22\3)*7\22*21\22
=22*3/21*(22*3/21-22*7/21)*7/22*21/22
=-66/3
=-22不明白(+22\7)*(22\7-22\3)*7\22*21\22=22*3/21*(22*3/21-22*7/21)*7/22*21/22=22*3/21*(-22*4/21)*7/22*21/22=-66/3=-22