the lowest elevation in Long Beach, California is 10 feet below sea level. The elevation of death valley is about 25 times lower than the elevation of Long Beach. what is the approximate elevation of death valley?

The elevation of Long Beach is 10 feet below sea level.
To write it numbers, we have to have a negative, since it's below sea level. Thus, it is at:
-10 feet
Now, the Death Valley is 25 times this.
So, we have to multiply 25 with it.
Thus,
-10 * 25 = - 250
Hence, the approximate elevation of the Death Valley