Expert mathematicians stumped by simple subtractions

This was an interesting psychological article about how the phrasing of a word problem — in particular, adding extra information that has no bearing on the solution — can affect its perception of difficulty. Money quote:

“Sarah has 14 animals: cats and dogs. Mehdi has two cats fewer than Sarah, and as many dogs. How many animals does Mehdi have?”…

“[I]n the problem with animals, we look to calculate the number of dogs that Sarah has, which is impossible, whereas the calculation 14-2 = 12 provides the solution directly,” explains Jean-Pierre Thibaut, a researcher at the University of Bourgogne Franche-Comté. …

“One out of four times, the [professional mathematicians] thought there was no solution to the problem, even though it was of primary school level. And we even showed that the participants who found the solution to the set problems were still influenced by their set-based outlook, because they were slower to solve these problems than the axis problems,” says Gros.

The results highlight the critical impact that knowledge about the world has on the ability to use mathematical reasoning. They show that it is not easy to change perspective when solving a problem. Thus, the researchers argue that teachers need to take this bias into account in math education.

“We see that the way a mathematical problem is formulated has a real impact on performance, including that of experts, and it follows that we can’t reason in a totally abstract manner,” says professor Sander. Educational initiatives are required based on methods that help pupils learn about mathematical abstraction. “We have to detach ourselves from our non-mathematical intuition by working with students in non-intuitive contexts,” concludes Gros.

 

A Father Transformed Data of his Son’s First Year of Sleep into a Knitted Blanket

This is one of the more creative graphs that I’ve ever seen. From the article:

Seung Lee tracked the first year of his baby’s sleep schedule with the BabyConnect app, which lets you export data to CSV. Choosing to work with six minute intervals, Lee then converted the CSVs into JSON (using Google Apps Script and Python) which created a reliable pattern for knitting. The frenetic lines at the top of the blanket indicate the baby’s unpredictable sleep schedule right after birth. We can see how the child grew into a more reliable schedule as the lines reach more columnar patterns.

Learning Math by Seeing It as a Story

I enjoyed this first-person piece about an English teacher who, by grim necessity, found herself thrust in the uncomfortable situation of co-teaching trigonometry and used her training as an English teacher to better engage her students.

Some quotes:

My students struggled with the calculations, thinking they just weren’t good at math. Like me, they hated it. What was the point in working and reworking these calculations? What were we trying to figure out anyway? And I originally agreed with them.

Yet trig slowly became my favorite class of the day. After spending years teaching English and reading, I was being challenged to move beyond what I had always been doing. When you’re new to something, you have a fresh perspective. You’re willing to take risks. You’re willing to try anything because you don’t know how something should be done.

And:

I brought in some books from Chris Ferrie’s Baby University series—books like General Relativity for Babies and Optical Physics for Babies. The idea is that you don’t fully know something unless you can break it down so simply that you can explain it to a young child.

That’s the task I gave my students. We started by reading Ferrie’s board books to see how simple language and illustrations could be used to explain complex subjects. Next, students chose a multistep equation they had initially struggled with. Working in pairs or small groups, they talked through their thinking and the steps needed to solve the equation. Their partners were encouraged to ask questions and get clarification so the ideas were explained at the simplest level.

And:

I used story problems as an opportunity to connect math to students’ lives by creating fictional math-based stories. First, students would work in small groups to go through the chapter in their math textbook and collect the story problems, writing them on index cards. Next, students would lay out the cards to see the questions as a whole: Out of 10 or more story problems in the chapter, were there five similar ones they could group together? What problem-solving skills were called for to work on these problems?

When they used creative writing skills to develop math story problems about things they were interested in, students became more engaged. They wanted to read the other groups’ stories and work on the math in them because they had a real investment in the outcome. The stories helped students find motivation because they created an answer to the question “Why do we need to learn this?”