50×(2×4)×25=50×2×4×25=100×100=100007×8×3×125 =3×7×8×125=21×1000=2100026×103=26×(100+3)=26×100+3×26=2600+78=2678501×12=(500+1)×12=500×12+12=6000+12=601225×(40+8)=25×40+25×8=1000+200=120039×14+61×14=(39+61)×14=100×14=1400163×8+37×8=(163+37)×8=200×8=1600202×13 =(200+2)×13=200×13+2×13=2600+26=262677×4×5 =77×20=154027×99 =27×(100-1)=27×100-27=2700-27=267348×250=12×4×250=12×1000=1200098+303=98+302+1=400+1=401 49+49×49=(1+49)×49=50×49=100÷2×49=4900÷2=245055×25+25×45 =(55+45)×25=100×25=2500 123×67-23×67=(123-23)×67=100×67=6700 39×101-39 =(101-1)×39=100×39=3900 99×64+64 =(99+1)×64=100×64=6400