**Primary Standards:**

**MAFS.3.MD.2.4****:**** **Generate measurement data by measuring lengths using rulers marked with halves and fourths of an inch. Show the data by making a line plot, where the horizontal scale is marked off in appropriate units— whole numbers, halves, or quarters.

**MAFS.3.MD.4.8****:** Solve real world and mathematical problems involving perimeters of polygons, including finding the perimeter given the side lengths, finding an unknown side length, ~~and exhibiting rectangles with the same perimeter and different areas or with the same area and different perimeters.~~

**Content Knowledge:**

In this unit, students extend their understanding of measurement and fractions by measuring objects to the nearest half and fourth of an inch. Students will also revisit line plots from 2^{nd} grade and record data to the half and fourth of an inch. Seeing both a line plot and a ruler as a number line helps students see the connection between these number concepts and models.

Perimeter is measured in linear units. In 3^{rd} grade, students explore the concept of perimeter, calculating the perimeter of polygons and solving problems related to perimeter. Through problem-based investigations and discussions, students develop an understanding of perimeter and the real-world applications for perimeter. In the next unit, students will investigate the relationship between area and perimeter.

**GCG 1 – Learning Goal: *** As a mathematician, I will be able to*** use strategies to fluently multiply by 7 ***Ongoing Fluency*

- Step 1: Use distributive property to connect x2 and x5 facts to gain fluency with x7 facts
*(e.g. 7×8 can be thought of as (5×8) + (2×8))* - Step 2: Decide when to apply the commutative property and other known facts for efficiency (
*e.g., students have another strategy for 7×4, they may decide to use double doubles strategy instead)*

**GCG 2 – Learning Goal: *** As a mathematician, I will be able to*** measure to the nearest whole, half, and quarter inch**

- Step 1: Use a ruler to measure objects to the nearest whole and half inch
- Step 2: Use a ruler to measure objects to the nearest quarter inch; make connections to half and quarter inch equivalences

**GCG 3 – Learning Goal: *** As a mathematician, I will be able to*** create line plots on a horizontal scale using wholes, halves, or fourths**

- Step 1: Interpret and plot measurement data on a provided line plot (with whole, half, and quarter inch units)
- Step 2: Generate measurement data and create a line plot where the horizontal scale is marked off in appropriate units (whole number, halves, or quarters)

**GCG 4 – Learning Goal: *** As a mathematician, I will be able to*** calculate and solve problems related to perimeter of polygons**

- Step 1: Define perimeter (as the linear measurement around a polygon) and measure perimeter of rectangles given side lengths
- Step 2: Solve real-world problems involving perimeters of polygons
- Step 3: Find the unknown side-length of a shape (especially rectangles) when given the perimeter

**GCG 5 – Learning Goal:*** As a mathematician, I will be able to*** use the relationship between area and perimeter to solve problems**

- Step 1: Compare and contrast the concepts of perimeter
- Step 2: Compare rectangles with the same area and different perimeters AND rectangles with the same perimeter and different areas
- Step 3: Solve a variety of real-world problems involving area and perimeter (using all four operations)