In grade 6, students learned how to write and interpret inequalities of the form \(x < c\) and \(x > c\). In this lesson, students begin to investigate inequalities of the form \(px<q\) and \(x + p < q\).
First, they are reintroduced to the notation < and > and reminded how inequalities can be expressed algebraically and graphically on a number line. A context is used to help students make sense of inequalities. The symbols \(\leq\) and \(\geq\) are introduced, which are the relevant symbols to use in many of the modeling problems they will see later on. Then they use substitution to check whether given values of \(x\) satisfy inequalities.
- Comprehend the terms “less than or equal to” and “greater than or equal to” (in spoken and written language) and the symbols ≤ and ≥ (in written language).
- Recognize that more than one value for a variable makes the same inequality true.
- Use substitution to determine whether a given value for a variable makes an inequality true, and justify (orally) the answer.
Let’s work with inequalities.
- I can explain what the symbols $\le$ and $\ge$ mean.
- I can represent an inequality on a number line.
- I understand what it means for a number to make an inequality true.