解:原式=(55x66+66x77)+(77x88+88x99)
=66x(55+77)+88x(77+99)
=66x132+88x176
=22x3x132+22x4x176
=22x(3x132)+22x(4x176)
=22x396+22x704
=22x(396+704)
=22x1100
=22x(1000+100)
=22x1000+22x100
=22000+2200
=24200