Example of the Envelope and Counter Model

Two expressions joined by an equal sign form what?

Put these steps in order to write an equation from an envelope and counter model.

In the envelope and counter model, the center dividing line stands for the equal sign ($=$).

In the envelope and counter model, match each part to what it stands for in the equation.

In the envelope and counter model, the envelope holds an unknown number of counters. One side has an envelope plus $3$ counters, and the other side has $8$ counters. Which equation matches this?

Match each algebra term to its meaning. Use the equation $x + 3 = 8$ as a guide.

The terms on one side of an equation, such as $x + 3$, form an algebraic _____.

In the envelope and counter model, what does the envelope stand for? What does one counter stand for? What does the center line stand for?

One envelope and three counters on the left equal eight counters on the right, showing $x + 3 = 8$. What does each part mean in algebra: the envelope, one counter, and the center line?

Write an equation: the sum of $x$ and 12 is 30.