What Is an Open Sentence in Math Terms?


What is an open sentence in math terms? I'm Bon Crowder and we're talking about open sentences and also closed sentences a little bit. So a sentence in math is kind of like a sentence in English. It has a subject and a verb. So the sentence, 8 + 14 is 72, that equals is like the is so that's our verb, 8 + 14 subject, verb is 72 is the predicate nominative maybe. So, this statement, this sentence is false right, 8 + 14 isn't 72, that's crazy talk. But the fact that it's false means it's a closed sentence. We know for sure whether it's true or false. Likewise, 3 + 4 is 7, the sentence is true. We know for sure. These are both closed sentences. This guy however, X - 7 = 4. I don't know if he's true or not. Now you can tell me well X is clearly 11, well if X is indeed 11, then that's a true statement but X is in disguise, I don't really know what he is, X could be 85. If X is 85, that's a false sentence. So because this is who knows, true or false, this is an open sentence. I'm Bon Crowder and that's what an open sentence in math is.

Bon Crowder has taught math to over 15,000 adults in living rooms, classrooms and conferences.