(50+4)x(50+6)=50x50+50x6+4x50+4x6=2500+300+200+24=2800+224=3024
解:原式=54x56=(55-1)x(55+1)=55²-1=3025-1=3024
(50+4)*(50+6)=(55-1)*(55+1)=55^2-1=3025-1=3024