Monday, May 20, 2013

6.EE.A.2 Stacking Bricks (y = 3x + 1)

6.EE.A.2  Write, read, and evaluate expressions in which letters stand for numbers.

Ideas in this lesson are based on
Stacking Bricks by Mark Duncan.

Prior to this lesson, students were already familiar with simple functions such as this one with the flower petals.

They knew how to generate t-charts and look for the rule. In this case, they were able to see a pattern of adding 7 or multiplying the number of flowers times 7 to determine the total number of petals.

They also understood how to write this as an equation, y (number of petals) = 7n (7 times the number of flowers).

To motivate my students and to connect mathematics with the real world, I showed them this photo of the Ennis House in Los Angeles. The home was designed in 1923 by Frank Lloyd Wright and has an interesting brickwork pattern.

Next, I told my students they had just been hired as brick masons, and needed to determine how many bricks they needed at the job construction site.

Using snap cubes, the students constructed each stage of the brick pattern and recorded this information on their t-charts.

 They drew the brick pattern on their papers, created ordered pairs, and starting graphing it.

Great job, Alejandra!  I like how you showed the pattern of "up 3, over 1." This represents the rate of change and 3/1 = 3, so each time you go up on your graph you are increasing the amount of bricks by three.

Where should the graph cross the y-axis?
What do you think the "plus one" in your formula means? Look at your brick pattern again. What did you start with?

At the close of the lesson, various groups presented their ideas and discussed the patterns they found.

Then I reinforced these concepts by having several come up and review ideas from our Gates and Fences lesson.

Excellent job everyone!  :)

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