Saturday, February 7, 2015

Circles: Circumference & Area

I LOVE CIRCLES. Circles are always fun to teach. A circle is one of the basic shapes. My almost seven month old son prefers circles to almost any other shape. They are round and easy to hold. We use circles so much in our everyday lives. We use circles on our cars, for our food containers, with our candles and we drink from circular objects. So circles hit home with every student I have ever taught and this activity is very easy for them to grasp. I love using this card sort activity with low level math students as well as all others, for the fact that it makes them double check their work. And in the end doesn't every math teacher love saying that..."DID YOU CHECK YOUR WORK?" "ARE YOU SURE THAT'S THE RIGHT ANSWER?" This activity helps them to see the difference between what numbers "they choose" to multiply and how the outcome can be very different. Also included is an extension about doubling diameter (which is ALWAYS a test question) and how that affects the outcome of circumference and area of a circle.

This lesson unit is intended to help you assess how well students are able to restate the formulas for the area and circumference of a circle and use them to solve problems; give an informal derivation of the relationship between the circumference and area of a circle.

Included in this lesson are:

-one formative assessment (pre-test) task

-card sort activity with concept development of circles (circumference and area)

-one extension activity for students to deepen their conception of circles (circumference and area)

-one summative assessment (post-test) task

-answer keys for all the assessments and activities

-how the lesson is tied to common core and mathematical practices 


For more activities visit:

Happy Teaching!

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