Advent Wreath Candles. Set on the branches of the wreath are four candles: three purple candles and one pink candle. In the center of the wreath sits a white candle. As a whole, these candles represent the coming of the light of Christ into the world. On the first Sunday of Advent, the first purple candle is lit.
In mathematics,  a coefficient is a multiplicative factor in some term of a polynomial, a series or any expression; it is usually a number, but may be any expression. In the latter case, the variables appearing in the coefficients are often called parameters, and must be clearly distinguished from the other variables.
The binomial coefficient is the number of ways of picking unordered outcomes from possibilities, also known as a combination or combinatorial number. The symbols and are used to denote a binomial coefficient, and are sometimes read as  choose ..