Current Digests: October 2025
The Exhausted Dad: Math unlocks popular kid trends
Coeur d’Alene Press, October 11, 2025
In this article from Coeur d’Alene Press, a father turns a new trend into an at-home lesson. “I only just discovered THE popular phrase of the elementary and middle school crowd in 2025,” Tyler Wilson writes. “Fans of numerology probably already know what I’m talking about, as does anyone currently living with children between the ages of 6 and 16.” Wilson crafted word problems to test his kids’ math skills, and the surprise answer delighted them.
Classroom Activities: six, seven, statistics
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- (All levels) The number 6 is known as a “perfect number” because the sum of all its divisors equals itself (1 + 2 + 3 = 6). Find the next perfect number by writing out the divisors of each number between 7 and 30.
- (Mid-level) Suppose you have 7 candies, each a different color. How many different sets of 6 candies can you make? How many if all the candies are the same color? (See our May digest about counting Skittle packs for more on this.)
- (Mid-level) How many whole numbers between 0 and 100 contain at least one 6 and one 7?
- How many between 0 and 1 million?
- (High level) How many of these numbers are prime?
- (All levels) Choose any number you want. Write a word problem based on the topics you are currently learning in math that results in that number.
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—Max Levy
Louvre robbery: Could a 50-year-old maths problem have kept the museum safe?
BBC, October 30, 2025
On October 19, the Louvre museum was robbed of historical jewelry worth hundreds of millions. For mathematician and writer Kit Yates, the incident brought to mind an old problem about how many security cameras are needed to surveil a polygon-shaped museum gallery. The answer is simple: Count up the number of corners in the room, and divide by 3. If only preventing burglary in the real world were so easy.
Classroom Activities: graphs, geometry
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- (Mid-level) Read the article, and examine the 3-coloring of Yates’ 15-sided gallery. Imagine placing a security camera at each of the red spots. Number the cameras from 1 to 4. In each triangular zone, write the number of the security camera that surveils it. Does Fisk’s solution work?
- (Mid-level) For each of the following polygons, use Fisk’s strategy to find an arrangement that surveils the entire shape with as few security cameras as possible.
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- (All levels) Modify the problem to make it more realistic.
- (Mid-level) With your modifications, do you think Fisk’s strategy will still work? Why or why not?
- (High level) In real life, galleries are three-dimensional. Can you generalize Fisk’s strategy to a 3D space? (Assume cameras can surveil in all directions.) Is the 2D or 3D problem more applicable to a real museum?
- (All levels) Modify the problem to make it more realistic.
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—Leila Sloman
How Math Helps Us Map The World
Science Friday, October 16, 2025
No map is perfect. Mapmakers who include many helpful details risk information overload, while keeping faithful to geography can make a map unreadable. But perhaps the most fundamental problem is mathematical: The Earth is round, while our maps are flat. In this Science Friday segment, Paulina Rowinska explains the consequences of this mismatch, and some of the other ways mathematics comes up in mapmaking.
Classroom Activities: geometry, curvature
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- Listen to the segment up until timestamp 05:50. Explain in your own words:
- (All levels) why it’s not possible to draw a flat map of the Earth with no distortion,
- (All levels) what the Mercator projection is,
- (Mid-level) which features of the Mercator projection map are accurate, and which are not,
- (Mid-level) why Mercator designed the projection the way he did.
- (All levels) Which of the following shapes have the same curvature as a sheet of paper? Explain your answer.
- cylinder,
- cone,
- football,
- tennis ball.
- (High level, Linear Algebra) You can calculate Gaussian curvature using a matrix called the shape operator. The Gaussian curvature for a shape is the determinant of that shape’s shape operator. Calculate the Gaussian curvature for the following shape operators. Do the results match your answers from the previous activity? Why do you think some shape operators change from point to point, while others don’t?
- sphere of radius $r$,$$S = \begin{bmatrix} –1/r & 0 \\ 0 & –1/r \end{bmatrix}$$
- a cylinder of radius 1,$$S = \begin{bmatrix} 0 & 0 \\ 0 & –1 \end{bmatrix}$$
- the ellipsoid$\frac{x^2}{2} + y^2 + \frac{z^3}{3} = 1$ at the point $(1,0,\sqrt{\frac{3}{2}})$,$$S = \begin{bmatrix} 2\sqrt{\frac{3}{5}} & 0 \\ 0 & \frac{2}{5}\sqrt{\frac{3}{5}} \end{bmatrix}$$
- the cone $x^2 + y^2 = (1 – z)^2$ at the point $(1/2,0,1/2)$,$$S=\begin{bmatrix} 0 & 0 \\ 0 & -\frac{2}{\sqrt{2}}\end{bmatrix}$$
- Based on the shape operator for a sphere, calculate the curvature of Earth.
- Listen to the segment up until timestamp 05:50. Explain in your own words:
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—Leila Sloman
The first supermoon of the year is approaching. Here’s what to know
Associated Press, October 5, 2025
On October 7, we saw the first of 2025’s three supermoons. Supermoons are a type of full moon that occurs when the Earth and the Moon are relatively close in their orbits. These events appear “up to 14% bigger and 30% brighter than the faintest moon of the year,” writes Adithi Ramakrishnan for AP News. Another supermoon event occurred on November 4, and a third will occur on December 5.
Classroom Activities: geometry, trigonometry, astronomy
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- (Mid-level) Supermoons can appear 14% larger in diameter than the full moons that are the most distant.
- Calculate the percent difference in area and circumference between both types of full moon.
- Based on your calculations, why do you think the supermoon appears 30% brighter than a faint full moon? (Hint: refer to this resource for more information on apparent brightness, or “flux.”)
- If the moon’s diameter appears 14% larger, does that mean it is 14% closer? Show your work.
- (Mid-level) In a total solar eclipse, the Moon passes between Earth and the Sun, briefly blocking out sunlight in its entirety.
- If the Sun is actually 400 times larger than the Moon, then what can you conclude about the relative distance from Earth to the Moon compared to the distance from Earth to the Sun? Show your work.
- What percent of the Sun’s area is blocked by the moon at the moment that the edge of the moon reaches the Sun’s center point in the sky?
- (Mid-level) A lunar eclipse occurs when Earth casts a shadow over the moon. Assume that Earth’s shadow on the moon has a radius about 2.5 times larger than the radius of the moon. Use this resource and calculator to calculate the “center distance” when the Moon is 25%, 50%, and 75% illuminated.
- (Mid-level) Supermoons can appear 14% larger in diameter than the full moons that are the most distant.
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—Max Levy
The physics of cacio e pepe
Scientific American, October 3, 2025
The secret to a perfect recipe is often ratios. Cacio e pepe is proof of that in pasta form. Cacio e pepe is a creamy Italian dish made with hard cheese and black pepper. The dish’s creaminess comes from an emulsion of melted cheese and starchy pasta water. “Cacio e pepe is a deceptively difficult dish,” according to Scientific American. Physicists recently investigated the science behind why the simple ingredients are so difficult to combine in the right way.
Classroom Activities: recipes, ratios, proportions
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- (All levels) The physicists conclude that to make a more foolproof cacio e pepe, you can add a small amount of corn starch. According to the scientific paper, the ideal recipe of pasta, cheese, water, and corn starch is: 300 grams, 200 grams, 150 grams, 5 grams. Calculate the following ratios:
- Pasta to cheese
- Water to cheese
- Cheese to water
- Corn starch to water
- Corn starch to pasta
- (All levels) If 300 grams of pasta is just enough for two people, calculate the required amounts of pasta, cheese, water, and corn starch for:
- 1 person
- 5 people
- 10 people
- (Mid-level) Based on the video, describe in your words what happens if a cook uses:
- Too much pasta water
- Too much cheese
- No pasta water
- Not enough heat
- (Hint: refer to Figures 1, 2, and 3 in the scientific paper.)
- (All levels) The physicists conclude that to make a more foolproof cacio e pepe, you can add a small amount of corn starch. According to the scientific paper, the ideal recipe of pasta, cheese, water, and corn starch is: 300 grams, 200 grams, 150 grams, 5 grams. Calculate the following ratios:
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Explore coverage of the recipients of the 2022 Fields Medals in Nature, Quanta Magazine, and The New York Times.
Read more recent digests of math in the media.
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