4th Grade Math Lesson

Shell Lengths & Sea Creatures: Line Plots with Fractional Data

Shared by A STEM Educator

4th GradeBTC Vertical Whiteboard FramingCCSS.4.MD.B.450 min

Learning Objective

Students will be able to construct a line plot with a fractional scale (halves, fourths, and eighths) to display measurement data, and solve addition and subtraction word problems using data from a line plot.

Lesson Overview

Students work in random groups of 3 at vertical whiteboards (VNPS) to progress from reading pre-built fractional line plots to constructing their own line plots with eighths and solving multi-step addition and subtraction problems using marine biology measurement data.

Materials

Vertical whiteboards or large chart paper (one per group)
Dry-erase markers (multiple colors per group)
Erasers or paper towels
Random grouping cards or name-draw tool
Task cards (one set per group, posted or distributed sequentially)
Rulers for drawing number lines
Printed Four-Quadrant Note Sheets (one per student)

Scaffolded Task Progression

1Task 1

The marine biology team recorded the lengths of $8$ shells on this line plot. Use it to answer the questions. ```coordgraph {"title":"Shell Lengths (inches)","xLabel":"Length (inches)","yLabel":"","xRange":[0,1.25],"yRange":[0,5],"xStep":0.25,"yStep":1,"polylines":[{"points":[[0,0],[1,0]],"color":"#000000"},{"points":[[0.25,0],[0.25,0.15]],"color":"#000000"},{"points":[[0.5,0],[0.5,0.15]],"color":"#000000"},{"points":[[0.75,0],[0.75,0.15]],"color":"#000000"},{"points":[[1,0],[1,0.15]],"color":"#000000"}],"points":[{"x":0.25,"y":1,"label":"X"},{"x":0.25,"y":2,"label":"X"},{"x":0.5,"y":1,"label":"X"},{"x":0.5,"y":2,"label":"X"},{"x":0.5,"y":3,"label":"X"},{"x":0.75,"y":1,"label":"X"},{"x":0.75,"y":2,"label":"X"},{"x":1,"y":1,"label":"X"}],"annotations":[{"type":"hbracket","y":-0.5,"x1":0,"x2":0.25,"label":"1/4"},{"type":"hbracket","y":-0.5,"x1":0.25,"x2":0.5,"label":"1/4"},{"type":"hbracket","y":-0.5,"x1":0.5,"x2":0.75,"label":"1/4"},{"type":"hbracket","y":-0.5,"x1":0.75,"x2":1,"label":"1/4"}]} ``` **Tick marks are at:** $\frac{1}{4}$, $\frac{2}{4}$, $\frac{3}{4}$, $1$ 1. How many shells measured $\frac{1}{2}$ inch? 2. Which length had the most shells? 3. How many shells were measured in total?

2Task 2

The research team measured $10$ more shells. Here is the line plot — but the scale is now in **eighths**. ```coordgraph {"title":"Shell Lengths (inches)","xLabel":"Length (inches)","yLabel":"","xRange":[-0.1,1.2],"yRange":[0,5],"xStep":0.125,"yStep":1,"polylines":[{"points":[[0,0],[1,0]],"color":"#000000"}],"points":[{"x":0.125,"y":1,"label":"X"},{"x":0.25,"y":1,"label":"X"},{"x":0.25,"y":2,"label":"X"},{"x":0.375,"y":1,"label":"X"},{"x":0.5,"y":1,"label":"X"},{"x":0.5,"y":2,"label":"X"},{"x":0.5,"y":3,"label":"X"},{"x":0.625,"y":1,"label":"X"},{"x":0.75,"y":1,"label":"X"},{"x":0.875,"y":1,"label":"X"}],"annotations":[]} ``` **Tick marks (left to right):** $\frac{1}{8}$, $\frac{2}{8}$, $\frac{3}{8}$, $\frac{4}{8}$, $\frac{5}{8}$, $\frac{6}{8}$, $\frac{7}{8}$, $1$ 1. How many shells measured $\frac{4}{8}$ of an inch? 2. What is the shortest shell length recorded? 3. How many shells are longer than $\frac{4}{8}$ inch?

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