standard_description: Use numbers expressed in the form of a single digit times an integer power of 10 to estimate very large or very small quantities, and to express how many times as much one is than the other. For example, estimate the population of the United States as 3 × 108 and the population of the world as 7 × 109, and determine that the world population is more than 20 times larger.
problem_activity: Task
A numeric expression like $5+(8 + 2)^2$ has one and only one value. What is it?
Consider the expression $5+(x + 2)^2$. What are some values it can have? Make sure you organize your work, so anyone can tell which value for the expression goes with which $x$ value.
How many different values can an algebraic expression like $5+(x + 2)^2$ have?
What is the difference between the expression $2x$ when it is all by itself and when it is in an equation like $2x = 12$ ?


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