Activity
A constraint is something that limits what is possible or reasonable in a situation.
For example, one constraint in a pizza party might be the number of slices of pizza each person could have, . We can write to say that each person gets fewer than 4 slices.
Look at the expressions you wrote when planning the pizza party earlier. Choose an expression that uses one or more letters.
What is the expression you are examining?
Your answer may vary, but here is an example.
What does the first letter represent?
Your answer may vary, but here is an example.
= number of toppings
What values would be reasonable for this first letter? (For instance, could the value be greater than 50? Is it possible for the letter to be a non-whole number? A negative number?)
Your answer may vary, but here is an example.
The cost of a topping is usually less than $2.00 per topping
What does the second letter represent?
Your answer may vary, but here is an example.
= number of pizzas ordered
What values would be reasonable for this second letter? (For instance, could the value be greater than 50? Is it possible for the letter to be a non-whole number? A negative number?)
Your answer may vary, but here is an example.
The number of pizzas ordered will probably be less than or equal to the number of students in the class.
Write equations or inequalities that represent some constraints in your pizza party plan. If a quantity must be an exact value, use the = symbol. If it must be greater than or less than a certain value to be reasonable, use the or symbol.
Your answer may vary, but here is an example.
if represents the delivery charge
Video: Writing an Inequality for the Constraint
Watch the following video to learn more about constraints.
Self Check
Additional Resources
Inequalities
One way to represent a constraint is to use an inequality symbol. For example, you may decide that at most 3 toppings should be on each pizza. This could be represented by t < 3, if represents the number of toppings.
On the number line, the numbers get larger as they go from left to right. The number line can be used to explain the symbols “” and “.”
is read “ is less than .” is to the left of on the number line.
is read “ is greater than .” is to the right of on the number line.
The expressions or can be read from left to right or right to left, though in English we usually read from left to right.
- For example, is equivalent to .
- For example, is equivalent to .
Inequality symbols | Words |
---|---|
is not equal to | |
is less than | |
is less than or equal to | |
is greater than | |
is greater than or equal to |
Let’s look at some specific examples:
Compare your answer:
17 is less than or equal to 26
Compare your answer:
12 is greater than 27 divided by 3
Compare your answer:
y plus 7 is less than 19
Try it
Try It: Inequalities
Translate the following statements into English phrases.
Compare your answer:
14 is less than or equal to 27
Compare your answer:
12 is greater than 4 divided by 2
Compare your answer:
x minus 7 is less than 1