| 2008+2007×2009 |
| 2008×2009−1 |
=
| 2008+2007×(2008+1) |
| 2008×(2008+1)−1 |
=
| 2008+2007×2008+2007 |
| 2008×2008+2008−1 |
=
| 2008×2008+2007 |
| 2008×2008+2007 |
=1.
| 2008+2007×2009 |
| 2008×2009−1 |
| 2008+2007×2009 |
| 2008×2009−1 |
| 2008+2007×(2008+1) |
| 2008×(2008+1)−1 |
| 2008+2007×2008+2007 |
| 2008×2008+2008−1 |
| 2008×2008+2007 |
| 2008×2008+2007 |