Hubby was given these for Chinese New Year.
Tangerines and oranges are auspicious Chinese New Year symbols. Tangerines when said in Chinese sounds similar to the word "luck" and orange when said in Chinese sounds like "wealth." Through the play of words, the Chinese associate the giving of orange and tangerine as having an abundance of happiness and prosperity.
The orange colour of the furits also symbolises the colour 'gold', hence it has an auspicious meaning to bring in good luck and wealth.
The red ang pao packet contains a certain amount of money, which (I think) is a token of goodwill and gesture.