Teacher Script & Notes
What to say / Spoken Script
An algebraic expression uses letters (variables) to represent unknown values. Here, we have a scale. The left pan has an unknown box $x$ and 3 weights. The right pan has 7 weights. This balance is represented by $x + 3 = 7$.
What to do / Action Guide
Display the balance scale with the variable box and weights.
Pedagogical Tips
Distinguish between expressions (no equal sign) and equations (with equal sign).
What to say / Spoken Script
Expanding a bracket like $a(b + c)$ means multiplying the term outside by each term inside. We can model this as the area of a rectangle of height $a$ and width $b + c$. The total area is $ab + ac$.
What to do / Action Guide
Show the area model partitioned into two sub-rectangles labeled $ab$ and $ac$.
Pedagogical Tips
Visualizing expansions as areas prevents the common mistake of forgetting to multiply the second term.
Step 1: Introduction
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