Allow the students to count the individual Hershey Bar pieces. The original Hershey bar should contain 12 individual pieces of chocolate. Have the students write down the number "12" on a piece of paper. Remind the students that this "12" will be the under part of the fraction or the denominator.
Break off the individual pieces of the Hershey bar. Start with the most obvious fractions, such as splitting the Hershey bar into half. Tell the students a story about how you devoured the first half of the bar, and then ask the question: "How many pieces of chocolate are remaining?" If you completely split the chocolate in half, there will be six pieces left. Tell the students to put a "6" on top of the fraction or the numerator. Half the chocolate will equal 6/12.
Break the chocolate in half again, asking the students to figure out how many pieces of chocolate are left out of the possible 12. From six, you can break the chocolate in half again, and then ask the students the same question that you presented in Step 2. The student will answer 3/12 or ¼.
Practice more complex fractions, such as 1/6 and 3/4 with more chocolate bars. With these fractions, teach the students about simplifying fractions. Divide the numerator into the denominator to simplify a large fraction. For example, 6/12 can be simplified into ½. Break off each individual piece, so that you have 12 individual pieces of chocolate, and then create the complex fractions.
Give the children each a candy bar, after the lesson, and allow them to break the pieces of the chocolate bar. Have them recreate the fractions to help them learn the fractions in Steps 2-4.