Evaluating algebraic expressions  Basic Algebra
Evaluating algebraic expressions
In this section, we are given models of cups and counters and asked to write the expressions represented by these models. We then use the variable x to represent the number of counters in each cup. We were first taught how to write expressions and solve for variables in a previous section. In this section, we are also asked to draw cup and counter models of given expressions. Finally, we are asked to write expressions for given phrases and evaluate the expressions using our variables.
Lessons

a)
i) What are variables?
ii) What is an expression?


1.
Below we have used ponds and tadpoles to model an expression. Write the expression and use the variable x to represent the unknown number of tadpoles in each pond.

3.
Write an expression for each phrase. Then, evaluate the expression.

4.
Evaluate the following expression, if $x = 7$ and $y = 9$