Question

1992.19911991-1991.19921992

tính bằng cách hợp lí

Answer 1

1992x1991x10001-1991x1992x10001

=1992x(10001x1991-10001x1991)

=1992x[10001x(1991-1991)]

=1992x[10001x0]

=1992x0

=0

Answer 2

\(=1992.1991.10001-1991.1992.10001=0\)