Students construct Fraction City to help them visualize adding and subtracting fractions. This lesson has various adaptations to help students visualize many concepts concerning fractions. In order to develop understanding of estimation, measurement, and computation, the mathematics curriculum should include problems which require students to apply appropriate tools and units of measurement, to develop effective estimation and computation strategies for producing reasonable results, and to calculate using appropriate tools such as mental mathematics, technology, manipulatives, and pencil-and-paper. This track well meets this goal.