Grade 3: Measuring and Comparing Area
comparing measures
measuring footprints
Adapted From:Measurement, Guide to Effective Instruction- Geometry Mobile On a computer? Click "file" then "make a copy" to save and make changes.
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Content
Expectations:
E2.9 use square centimetres (cm2) and square metres (m2) to estimate, measure, and compare the areas of various two-dimensional shapes, including those with curved sides
Key Concepts:
Area tells how much material is required to cover a shape on the surface of an object. Shapes that look different can have the same area
Learning Goal
We want students to understand...
That the area of a two dimensional shape can be measured by covering the shape with squares (e.g., centimeter cubes, squares on grid paper) arranged in an array.
Success Criteria
demonstrate an understanding that area is measured by finding the number of square units that cover a surface;
use appropriate strategies for measuring area (e.g., arrange centimeter cubes in arrays, use centimeter grid paper);
find the number of square units in an array (e.g., using repeated addition, using skip counting, using multiplication);
order and compare surfaces by area.
Materials
Centimetre Grid Paper (1 per student)
BLM 5- Finding the area of rooms
Pedagogy
Minds On
Provide each student with Centimetre Grid Paper.
https://www.math-drills.com/graphpaper/graph_paper_1_cm_001.php
Have each student, with the help of a partner, trace an outline of the sole of one shoe on the grid paper. Ask the student to estimate the area of his or her footprint, in square centimetres, and to record the estimate on the page.
Action!
Next, have each student find the area of his or her footprint. Watch to see whether the students find partial squares that have a combined area of approximately one square centimeter (e.g., two half-squares have an area of one square centimeter).
As well,observe the strategies that they use to find the total number of square centimeters. For example, students might:
•count all the squares individually;
•draw and find the area of a rectangle that includes most of the squares, and then add on squares outside the rectangle;
•divide the area of the footprint into arrays, find the number of squares in each array,and then add the areas of the arrays.
Consolidation Ideas
Discuss the strategies that students used to find the areas of their footprints and put these strategies in an anchor chart.
Independent Task / Assessment Opportunities
Provide Students with BLM 5 Finding the Area of Rooms (on the next page). Explain that the diagrams show floor plans of rooms. Point out that the floors of the rooms are covered with square tiles and that furniture covers parts of the floors. Ask the students to find the area of each room and to record on their page how they found each area. Have the students share their findings with a partner. Provide the students with an opportunity to explain to the class how they found the areas of the rooms.
SEL Self Assessments (French and English)