原式=（666-11）+654*655-（321-11)
=655+655*654-310
=655*655-310
=(600+55)*(600+55)-310
=360000+2*33000+[(50+5)*(50+5)]-310
=360000+66000+（2500+500+25）-310
=426000+3025-310
=429025-310
=428715