小学数学乘法题

=(100+3)*12

=100*12+3*12

=1200+36

=1236

2.20*55

=20*(50+5)

=20*50+20*5

=1000+100

=1100

3.24*205

=24*(200+5)

=24*200+24*5

=4800+120

=4920