I like apples, but I used to hate dealing with the core. After thinking about the way the cuts are made, I found a simple way to cut and core at the same time. It takes a little practice, but it works like a charm.
Make the first cut as shown below. You can cut clean down to the table, but I like to leave a little apple at the bottom to keep the slices together while I cut them.
Rotate the apple a little and make the next cut, starting where the knife intersects the first cut. Keep rotating and slicing until you have sliced eight slices. The core will be octagonal and will just fall away.
That’s all there is to it. Enjoy.