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;
故答案為:1.
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 |