I must give credit to former-colleague “Mr. OC” at Nitschmann Middle School for this novel way to introduce compound events. Ever since I saw him do it, it’s become a regular part of my practice. So easy, so effective, and the kids’ reactions are priceless!
First, tell students they are having a quiz… surprise! Everyone number your papers from 1 to 10.
Next, say with appropriately dramatic pauses,
Teacher: “Number one… true… or false?”
Students: Waiting patiently for the actual question.
Teacher: “Number two… true… or… false?”
Students: “Wait, what was number one?”
Teacher: “Number one was true… or false.”
Students: “No… the QUESTION for number one!?!”
Then a few of them start to catch on. And… a few still have no idea what’s going on.
I love teaching middle schoolers.
Teacher: “Number three… wait for it… false… or true?”
At this point, some students have randomly answered all ten questions while others wait for me, just in case I decide to switch it up on them.
After dramatically asking the question ten-fold, it’s time to “grade” our papers. I read the “correct answers” which I’ve randomly jotted down ahead of time, so as not to be persuaded by my students. They cheer at “correct” responses and scoff at the ones they missed. It’s a riot.
We talk about the probability of getting problem #1 correct, #2 correct, and so on. I ask, “What’s the probability someone would get a perfect paper?” After writing one half on the board ten times, we decide multiplying the probabilities together will answer our question.
1/1,024 it is.
“How many people got a perfect paper?”
No one has. As a matter of fact, these quiz scores are usually pretty crappy. However, the impression this little task makes on students is worth it! 🙂
Irony –> I *just* stumbled upon this great video follow-up! How neat!