Explanation:
The "fraction of the cards" is the number of cards for the year divided by the total number of cards for all of the years. Then divide by their GCF to reduce the fraction into its lowest terms.
Answer:
[tex]\begin {array}{c|c||l}\underline{Year}&\underline{\#\ of\ Cards}&\underline{Fraction\ of\ Total\ Cards}\\\\2009&12&\dfrac{12}{60}\div \dfrac{12}{12}=\dfrac{1}{5}\\\\2010&18&\dfrac{18}{60}\div \dfrac{6}{6}=\dfrac{3}{10}\\\\2011&10&\dfrac{10}{60}\div \dfrac{10}{10}=\dfrac{1}{6}\\\\2012&20&\dfrac{20}{60}\div \dfrac{20}{20}=\dfrac{1}{3}\\\end{array}[/tex]
