When finding an integer you figure out if the integer is positive or negative; positive as in being above a certain point, such as sea level, and negative as in being below that certain point. Being positive might also mean going up or moving forward; and vice versa for being negative.
1. 282 feet below, so it is -282
2. 3 inches more, so it is 3
3. gained 5 points and lost 4 points, so 5 & -4
4. The airplane pilot could have gone down in altitude by 100 meters, or could have gone up in altitude by 100 meters.