Question

103×12 20×55 24×205 用乘法分配律计算

Answer 1

103*12=(100+3)*12=1200+36=1236
20*55=20*(50+5)=1000+100=1100
24*205=24*(200+5)=4800+120=4920

Answer 2

103×12+ 20×55 +24×205
=206*6+20*5*11+24*206-24
=206*（6+24）+100*11-24
=206*30+1100-24
=6180+1100-24
=7280-24
=7256