巧算:28X48加96,63x7除以63x7,1999加999x999贵
问题描述:
巧算:28X48加96,63x7除以63x7,1999加999x999贵
答
28*48+96=14*96+96=(14+1)*96=15*(100-4)=1500-60=1440
63*7/63*7=63/63*7*7=49
1999+999*999=1999+(1000-1)*(1000-1)=1999+1000000-2000+1=1000000