This set of activities is the math portion of an interdisciplinary unit on westward expansion (most commonly taught at the 8th grade level). The students will first explore using a scale and proportions to find the actual distances from a group of famous trails. They will then use number sense to understand how the cost of the Louisiana Purchase relates to today's economy. Last, they will explore scale again by creating a scale drawing of a covered wagon using real life dimensions. Materials need for these activities include: string, rulers, compasses, calculators, 8 1/2 x 11 paper or longer if possible (for the drawing), and copies of trail maps (I used copies from the Social Studies teacher's book).