A number of means a group of and can be used with great, large, small to emphasize the quantity.

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• A number of tourists have been abducted by a terrorists.

• There were a number of important historical points in the textbook .

• The scene was filmed from a number of different angles.

• A great number of nations expressed opposition to Bush’s military action against Iraq.

• A large number of university students were imprisoned.

• A large number of letters have been sent to the customers.

• A small number of people have a Ferrari car in Turkey.

• A small number of children are educated at home.