• In the subquery, select the average total goals by adding home_goal and away_goal.
  • Filter the results so that only the average of goals in the 2013/2014 season is calculated.
  • In the main query, select the average total goals by adding home_goal and away_goal. This calculates the average goals for each league.
  • Filter the results in the main query the same way you filtered the subquery. Group the query by the league name.