Understanding Soccer

Each team consists of not more than eleven players, one of whom is the goalkeeper.

An official match may not start if either team consists of fewer than seven players.

Up to a maximum of three substitutes may be used in any match played in an official competition organised under the auspices of the World Governing body FIFA, the confederations or the national associations.

In other competitions the rules must state how many substitutes may be nominated, from three up to a maximum of seven.

The duration of an an official match is 90 minutes played in two halves - each half lasting 45 minutes.