Aroller coaster climbs 110 feet from ground level then drops 65 feet before climbing another 135 feet. how far does the coaster need to drop or climb to be back at ground level can can some me

The roller coaster starts at ground level.
Start: ground level, 0 ft altitude.
Climbs 110 ft: now it is at 0 ft + 110 ft = 110 ft altitude
Drops 65 ft: now it is at 110 ft - 65 ft = 45 ft altitude
Climbs 135 ft: now it is at 45 ft + 135 ft = 180 ft altitude
Since after the last step it is at 180 ft altitude, for the altitude to go back to 0, you must do 180 ft - 180 ft since 180 ft - 180 ft = 0 ft, ground level. The -180ft (the subtraction of 180 ft) part is a 180 ft drop. Therefore, the roller coaster needs to drop 180 ft to get back to ground level.