Distinguishing between open and closed sentences - JSS1 Mathematics Lesson Note

Closed Sentences: These are mathematical statements that are either true or false. They don’t contain any variables. For example:

2+3=5 (True)

7−2=6 (False)

These sentences are called "closed" because their truth value can be determined immediately.

Open Sentences: These are mathematical statements that contain variables. The truth of these sentences depends on the values assigned to the variables. For example:

𝑥+3 = 5

2𝑦−4 = 6

These sentences are "open" because we cannot determine if they are true or false without knowing the value of the variables 𝑥 and 𝑦.