Question

So sánh : 99 x 101 ; 100 x 100

Answer 1

Xét 99 x 101

= ( 100 - 1 ) x ( 101 - 1 )

= 100 x 100 + 1 x 101 - 1 x 101 - 1 x 1 

= 100 x 100 - 1

Vậy 99 x 101 < 100 x 100

Answer 2

nhầm chút 

Xét 99 x 101

= ( 100 - 1 ) x ( 100 + 1 )

= 100 x 100 + 1 x 101 - 1 x 101 - 1 x 1 

= 100 x 100 - 1

Vậy 99 x 101 < 100 x 100