Question

897乘898减899乘896分之897乘897减896乘898

Answer 1

(897 * 897 - 896 * 898) / (897 * 898 - 899 * 896)

= (897^2 - (897 - 1)*(897 + 1)) / (897*898 -(898 + 1)*(897 - 1) )

= (897^2 - 897^2 + 1 ) / (897 * 898 - 897 * 898 + 898 - 897 + 1)

= 1 / ((898 - 897) + 1)

= 1 / (1 + 1 )

= 1 / 2