In 3-5 sentences describe the apportionment system for state legislative districts?

The simplest and most universal principle is that elections should give each voter's intentions equal weight. This is both intuitive and stated in historical documents such as the Fourteenth Amendment to the United States Constitution (the Equal Protection Clause). However, there are a variety of historical and technical reasons why this principle is not followed absolutely or as a first priority.

Common problems:

Fundamentally, the representation of a population in the thousands or millions by a governing body that is much smaller involves arithmetic that will not be exact. Although it could make representation more exact for a representative's vote in the governing body to be weighted according to the number of his constituents,[1] it avoids complexity and awkwardness if each representative has exactly 1 vote.

Over time, populations migrate and change in number, and preferences change. Governing bodies, however, usually exist for a defined term of office. While Parliamentary systems provide for dissolution of the body in reaction to political events, no system tries to make real-time adjustments to reflect demographic changes. Instead, any redistricting takes effect at the next scheduled election.