^{3}series, students explore an interesting simulated or real-life problem connected to their world and use their Mathematician’s Journals to think, write, and act like mathematicians to solve the problem.

» Treasures From the Attic: Exploring Fractions

In this unit, students are introduced to two children, Tori and Jordan, who uncover hidden treasures in their grandparents’ attic from a general store that their great grandparents used to own. These treasures lead to an interesting exploration of fraction concepts. The focus of the entire unit is on making sense of fractions and operations with fractions rather than on learning algorithms to perform computations.

» The Tenth Street Pet Sanctuary: Understanding and Using Decimals

This unit is an introduction to the decimal numeration system focusing on conceptual understanding and operations with decimals. Students learn how the powers of ten are used to create decimals and learn about the density property of the rational number system. Students also work with the four operations: addition, subtraction, multiplication, and division of decimals. The focus is on developing a strong understanding of the meaning of these operations with decimals by understanding the context and constructing models and algorithms that make sense of the situations.

» At the Mall With Algebra: Working With Variables and Equations

When we hear the word *algebra*, we generally think about high school curriculum. In earlier grades, the emphasis is on developing algebraic reasoning and that is what this unit emphasizes. Students represent and analyze mathematical situations using algebraic symbols and in doing so they come to understand the basic notion of equality and equivalent expressions. They learn how variables are used to represent change in quantities and also to represent a specific unknown in an equation. They solve equations and sets of equations using a variety of methods.

» Getting Into Shapes: Exploring Relationships Among 2-D and 3-D Shapes

In this unit, students explore 2- and 3-dimensional shapes with a focus on their properties, relationships among them and spatial visualization. The reasoning skills that they build upon in this unit help them to develop an understanding of more complex geometric concepts.