Integers — Definition & Examples

A Matryoshka doll, otherwise known as a Russian nesting doll, is comprised of a series of wooden dolls of decreasing size placed in one another (the largest is the outermost, then the second largest is the second outermost, etc.). If the categories of rational numbers, whole numbers, natural numbers, and integers were made into a Matryoshka doll with the biggest set corresponding to the largest doll, which position would integers be in? Assume that the largest doll is in the first position.