What is the difference between an expression and an equation? Write your thoughts in words, and then give at least
four examples to illustrate your thinking.
The two sides of the image below are balanced. On one side we have boxes labeled and on the other side we have
boxes each representing one unit. 
Draw two other examples of things you know would be balanced from this information. Explain your thinking in each case and write an equation that corresponds to each pan balance that you draw.
The two sides of the image below are balanced. On one side we have one box labeled and five unit blocks. On the
other side we have unit blocks. 
Draw two other examples of things you know would be balanced from this information. Explain your thinking in each case and write an equation that corresponds to each pan balance that you drew.
Consider the equation .
- (a)
- Solve this equation by using pictures of pan balances. Draw a new pan balance for each step. Explain your thinking, paying close attention to how you know the balance is still balanced at each step.
- (b)
- Write equations that correspond to each pan balance drawing from the previous part. Explain how you know your equations are correct.
- (c)
- Solve the original equation using algebra. What do you notice?
- (a)
- Give another example of an equation you could solve with a pan balance, and then solve it using both pictures and equations as we did in the previous problem.
- (b)
- Give an example of an equation that you could not solve using a pan balance, and explain how you know that you could not use a pan balance for this equation.