# A.2.1.3 What are the Constraints?

A constraint is something that limits what is possible or what is reasonable in a situation. For example, one constraint a teacher has to work with is the amount of time in a class period or the number of school days in a year (both of these might be a fixed number). Another constraint might be the number of students in a class (which may vary by class, but is usually no more than a certain number).

One constraint in a pizza party might be the number of slices of pizza each person could have, s. We can write s < 4 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. For each letter, determine what values would be reasonable. (For instance, could the value be a non-whole number? A number greater than 50? A negative number? Exactly 2?)

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 or less than a certain value to be reasonable, use the < or > symbol.