There is no definite number for how many tournament a given player will play in one year...
But every player will do everything to join the 4 "big" ones: Australien Open, French Open, Wimbledon and US Open - mainly because of the big prestige and money prizes these represent..
And there is a rule that they atleast have to play 4 of the so called "500 Series tournaments"
And the top 8 players in the world also has a mandatory appereance on " ATP World Tour Finals"
Other than those, the players join for money and world ranking points (which 100's of tournaments each year represent)
there are 4 players in lawn tennis doubles.
120 million amateur players worldwide
There are many tennis players training in Florida because they have some of the best tennis players in the world including Bolliteri tennis academy.
2 - 4 players.
There is always 128 players are selected.
In 2012 (figures issued in late 2013 by the French ministry of sports), the French Tennis Federation had 1,111,136 registered players. In number of registered players, tennis is second only to football in France. 30% of the registered players were women. Many people who are playing tennis only occasionally are not registered.
223
2
Two or four.
4
two
70,000,000 (seventy million players worldwide)