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Teacher Notes (not visible to students)

This activity is meant to be teacher-directed. It is an introduction to variable expressions and specifically the meaning of the terms variable, constant, and coefficient. This is taken from Jo Boaler's example for visualizing variable expressions as a representation of a growing pattern. The shape begins as a cross with five green squares. The green stays the same in each case representing the constant. The top and the bottom of the cross grow each time. Because there is a red square added to the top and the bottom in each new case the growth is 2x each time. The expression that describes the pattern is 2x + 5. Students will see the green 5 is "constant" and does not change. They will see that the red squares "vary" depending on the case. Have them use the expression to complete the chart for another case in the future (case 10, or case 15, or case 100...)