Writing and evaluating numerical expressions involving whole-number exponents, as well as writing expressions with numbers and letters as placeholders is essential. It's also important to identify parts of an expression using mathematical terms, such as sum, term, product, factor, quotient, and coefficient. Evaluating expressions with specific values for their variables is also a key process, and can include situations from real-world problems. Other skills include understanding and applying the properties of operations to generate identical expressions and identifying when two expressions are the same.

Understanding how to solve an equation or inequality is crucial, involving a process of identifying which values make the equation or inequality valid. Variables can be used to represent numbers, formulating expressions to solve real-world or mathematical problems. Inequalities can be written to represent real-world constraints or conditions, along with understanding that these inequalities can have infinite solutions.

The use of variables to represent quantities in real-world problems that change in relation to one another is also vital. Equations can be written expressing one variable in terms of another, and relationships between the variables can be analyzed using graphs and tables. This process can be tied back to real-world scenarios, such as motion at a constant speed.