Initial position: 10 feet below sea level
Dives down: 12 more feet
Take the sea level as the 0, if the initial position is 10 ft below sea level it means -10ft relative to sea level. Then, if dives down 12 more ft subtract from -10ft the 12ft to get the final position:
![-10-12=-22](https://img.qammunity.org/2023/formulas/mathematics/college/pp594vo4vvhsa4g40bn3xzfqbszsdheq73.png)
Then. the final position relative to sea level is -22 feet