Cogito
Grade 7 Math · Chapter 6 · Lesson 4
Solving Inequalities
One step where the rules change.
10 problems · about 19 minutes · 7.EE.B.4
What this lesson teaches
The child solves inequalities and reverses the symbol when multiplying or dividing by a negative.
- Inequalities are solved the same way as equations.
- Multiplying or dividing by a negative reverses the symbol.
- Test a value from your answer in the original to be sure.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — Solving p(x + q) = r: 6(x + 2) = 42. What is x?
Answer 5
Why x = 5.
Review — Solving px + q = r: 4x + 3 = 23. What is x?
Answer 5
Why x = 5.
Review — Two-Step Equations: Solve 7x − 2 = 33.
Answer 5
Why x = 5.
Warm Up
Straightforward practice. Get the method working first.
3 problems4x > 20. Smallest whole number x?
Answer 6
Why 6.
x + 4 < 9. Largest whole number x?
Answer 4
Why x < 5.
3x > 12. Smallest whole number x?
Answer 5
Why x > 4.
Build It Up
The same ideas with more to keep track of.
2 problemsDoes dividing by a negative reverse the symbol? Answer 1 for yes, 0 for no.
Answer 1
Why Try it on 3 < 5.
2x + 1 < 11. Largest whole number x?
Answer 4
Why x < 5.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Inequality: 2x < 10. What is the largest whole number x can be?
Answer 4
Why 4.
The Reversal: −3x > 9 gives x < −3. What is the largest whole number x can be?
Answer -4
Why −4.