Question

how to cut a cake in 8 pieces in 3 moves

Answer 1

Cut 1 – Down the center of the cake (vertically) leaving two equal halves.
Cut 2 – Across the center of the cake (horizontally) leaving four equal slices.
Cut 3 – Through the middle edge of the cake slicing all four of the pieces in equal halves, leaving eight equal slices (four equal tops and four equal bottoms).