20乘55脱式计算过程如下：
55×20
=（50+5）×20
=50×20+5×20
=1000+100
=1100
脱式计算过程如下解:55×20=（50+5）×20=50×20+5×20=1000+100=1100
=20x5x11=100x11=1100
