How do you write sets of numbers for negative integers?

To write a set of negative integers, you use curly braces and list the integers, often starting from -1 and going downwards. For example, the set of the first five negative integers can be written as {-1, -2, -3, -4, -5}. If you want to represent all negative integers, you can denote the set as {x ∈ ℤ | x < 0}, meaning all integers x that are less than zero.