Cogito
Grade 6 Math · Chapter 6 · Lesson 5
Inequalities on a Number Line
When the answer is a stretch, not a point.
10 problems · about 17 minutes · 6.EE.B.8
What this lesson teaches
The child writes an inequality of the form x > c or x < c and represents its solutions on a number line.
- An inequality is satisfied by a whole stretch of numbers, not one.
- An open circle leaves the endpoint out; a filled circle includes it.
- The wide end of the symbol faces the larger side.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — Writing Equations from Stories: 7n = 63. What is n?
Answer 9
Why 9.
Review — Inequalities and Two Variables: c = 6w. What is c when w = 8?
Answer 48
Why 48.
Review — Solving One-Step Equations: Solve 8n = 96.
Answer 12
Why n = 12.
Warm Up
Straightforward practice. Get the method working first.
3 problemsSmallest whole number satisfying x > 11?
Answer 12
Why 12.
Does 7 satisfy x > 5? Answer 1 for yes, 0 for no.
Answer 1
Why 7 is right of 5.
Does 5 satisfy x > 5? Answer 1 for yes, 0 for no.
Answer 0
Why The circle is open.
Build It Up
The same ideas with more to keep track of.
2 problemsSmallest whole number satisfying x > 2?
Answer 3
Why Just past 2.
Largest whole number satisfying x < 6?
Answer 5
Why Just below 6.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Ride: You must be over 8 to ride. Is 8 allowed? Answer 1 for yes, 0 for no.
Answer 0
Why No — the circle is open at 8.
The Smallest Whole: What is the smallest whole number that satisfies x > 8?
Answer 9
Why 9.