1988+1989×19871988×1989−1=_.

问题描述:

1988+1989×1987
1988×1989−1
=______.

1988+1989×1987
1988×1989−1

=
1988+1989×(1988−1)
1988×1989−1

=
1988+1989×1988−1989
1988×1989−1

=
1988×1989−1
1988×1989−1

=1;
故答案为:1.