To slice it in quarters, start with a knife if you don't have a peeler. After you've cut the apple into quarters, peel it, then remove the core.
A peeler will allow you to peel the apple more cleanly. If you don’t have an apple corer, cut the four sides of the peeled apple, avoiding the core. Then place the pieces flat on the board and slice them to the desired thickness.
If you don't have an apple corer but you have a mellon baller, cut the apple in half after peeling it. Cut out both stem ends with a knife and remove the core using your mellon baller. Then you can slice the apple at a slight angle.
There are two methods of slicing an apple into rounds. In the first method, you cut off both ends, then use an apple corer to remove the core. Peel the apple with a peeler or knife, then carefully slice it while holding it firmly to prevent it from slipping.
The other method consists of slicing it without removing the core first. Once you've peeled it, slice it carefully, removing the seeds and stem as you go. This method will leave a pretty star pattern in the center of each slice, perfect for decorating a pie.