The vinculum

I’m teaching about the vinculum.

“What is the line that separates the numerator and denominator?” I ask my class.

No one knows.

Most people don’t know.

You probably didn’t know.

“It’s called the vinculum,” I say. It’s the line that separates the numerator and the denominator in a fraction.”

I write the word on the board.

“What might you compare the vinculum to?” I ask. “To help you remember what it does?”

At least three children simultaneously shout out the word “Divorce!”

I didn’t see that one coming.

But I’m struck by how open and honest my students are about the topic, and how much the world has changed since I was a kid. Surprisingly, divorce rates have decreased significantly since their peak in the early 1980s, falling from approximately 5.3 divorces per 1,000 people in 1981 to around 2.3 today.

But divorce was a taboo topic when I was growing up. We didn’t speak about it as openly and easily as my students do. Even though divorce was more common, we avoided the topic whenever possible.

We certainly didn’t use it as a metaphor for the vinculum.