Number ten can be expressed in a variety of ways. For instance, if you are playing a game of bingo, number ten can be referred to as "two little ducks" due to the two oval shapes resembling ducks. In some cultures, ten is believed to be a lucky number and is referred to as "perfect ten." Another term for ten is "decade," which often refers to a period of ten years. In music, ten can be represented by the symbol "X," as in "Roman numeral ten." Lastly, in sports, ten is often associated with the highest level of achievement and is referred to as the "perfect 10".