Math Curmudgeon
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mathcurmudgeon.bsky.social
Math Curmudgeon
@mathcurmudgeon.bsky.social
670 followers 460 following 490 posts
~40 years teaching HS math, physics & computer science. #iteachmath
He/Him/Sir/Mr. M

Alaxandr
Combat Archer, Northern Army
SCA: Society for Creative Aachronism
"Þæs ofereode, þisses swa mæg."
"That passed; this too shall pass."
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mathcurmudgeon.bsky.social
Math Curmudgeon @mathcurmudgeon.bsky.social · Mar 13
#mathstoday #iteachmath
Geometry students played CONSISTENCY with the polygons set. Lots of fun had by all.

It's a Geometry game. Each player lays down a card that is consistent with the previously played cards. If you'd like to play-test it:
drive.google.com/drive/folder...
Center cards: Area is less than 70 The shape is a pentagon. Player on the left has played "The shape is regular" The next player must choose between The measures of all interior angles are integers Adjacent angles add to 180 Angle Bisectors pass through the opposite vertex. Exterior angles are 30
mathcurmudgeon.bsky.social
CONSISTENCY is a game for Geometry students. Each player lays down a card that is consistent with the previously played cards.
matharguments.com/consistency....
(Links in right margin)

#iteachmath #mathgames #geometry #matheducation #MTBoS #MathsToday
The Consistency Game
matharguments.com
September 20, 2026 at 8:45 PM
mathcurmudgeon.bsky.social
The most annoying thing I've run in 40+ years is creating curricula and materials in one format and having to re-create it all in the next format.

I started on dirty-purple. 20+ sets of conversions later, here we are.

No, I'm not moving my presentations to your website.

#ITeachMath #MathsToday
August 31, 2026 at 2:32 PM
mathcurmudgeon.bsky.social
Play-Testers wanted!

"N is a Number" is a CONSISTENCY variation for Middle School.

Each player lays down a card that is consistent with the previously played cards. You can find rules and card sets at the link.
#iteachmath
#mathstoday

bit.ly/TheConsisten...

1/3
July 15, 2026 at 5:15 PM
mathcurmudgeon.bsky.social
CONSISTENCY is a Geometry game for Geometry students. Each player lays down a card that is consistent with the previously played cards. You can find rules and card sets at the link (google drive link).
#iteachmath #MathToday #MathsToday #Geometry

drive.google.com/drive/folder...
Center cards: Area is less than 70 The shape is a pentagon. Player on the left has played "The shape is regular" The next player must choose between The measures of all interior angles are integers Adjacent angles add to 180 Angle Bisectors pass through the opposite vertex. Exterior angles are 30
April 21, 2026 at 6:21 PM
mathcurmudgeon.bsky.social
I like asking questions like:
Why would people write this number in the following ways?
30,000,000,000.0
30.000.000.000,0
30 000 000 000
3*10^10
30*10^9
30 billion
March 22, 2026 at 6:16 PM
mathcurmudgeon.bsky.social
#mathstoday #iteachmath
Geometry students played CONSISTENCY with the polygons set. Lots of fun had by all.

It's a Geometry game. Each player lays down a card that is consistent with the previously played cards. If you'd like to play-test it:
drive.google.com/drive/folder...
Center cards: Area is less than 70 The shape is a pentagon. Player on the left has played "The shape is regular" The next player must choose between The measures of all interior angles are integers Adjacent angles add to 180 Angle Bisectors pass through the opposite vertex. Exterior angles are 30
March 13, 2026 at 4:08 PM
mathcurmudgeon.bsky.social
Looking for some teachers to play-test this Geometry review game. You can find rules and card sets at the link (google drive link). Players have cards with either an image or a statement about a figure and lays down one that doesn't contradict anything else.
drive.google.com/drive/folder...
Consistency - Google Drive
drive.google.com
March 10, 2026 at 9:37 PM
mathcurmudgeon.bsky.social
It's a Geometry game that @unsolvedmre.bsky.social had tossed into the ether. I tweaked it some, set it aside for a couple years, and tweaked it some more. Here are the instructions, and some of the cards.

What do you think?
Playable?
Enjoyable? (For your students, ...)
#ITeachMath
Consistency! Consistency! is designed for students who are about halfway through a typical Geometry course. It’s excellent for review and revision because it promotes discussion and argument. GAME PLAY A Round of Play: - The cards are dealt counter-clockwise and any remaining cards are set face down to form a draw pile. Each player gets the number of cards as in the table. - The player to the dealer’s right begins the round by placing any card face-up in the middle of the table. - Each player in turn lays down a card (face-up) that is consistent with all cards already in play: For example: A middle card has the image at right. The next card could be “cos⁡〖A=1/2〗 ” or “one exterior angle is 120° ” but not “Side lengths are Pythagorean triples.” - A player who cannot lay down a consistent card draws 1card and play moves to the right. - Players can bluff and lay down a card that is inconsistent with one or more of the cards already played. Anyone can challenge a card at any time. Allow 30 seconds or so for players to decide whether to challenge. End of the Round: • The round ends in one of two ways 1. A player lays down a consistent card and no one else around the table can do so, then that player wins the round. Example: 5 people (A, B, C, D, E) are playing and C plays a consistent card. If none of the players D, E, A, and B can play a card in turn, then C has “played the last consistent card” and wins the round. In a two-player game, the second player must pass twice. 2. If a player in their turn lays down their last card (and it’s consistent!), they immediately win the round. • The player that wins the round receives 1 point for each card in play and sets these cards aside. Gloating and performing a TikTok dance are optional. • The dealer’s role moves counter-clockwise. • The rest of the cards are combined, shuffled, and a new round is dealt. Challenges: • If a player lays down an inconsistent card, then anyone can challenge the card by describing how it is inconsistent. It is important to remove inconsistent cards because further play is impossible. • Penalties depend on when the challenge is made: o In the 30 seconds: If the challenge is upheld, the “offender” takes back the inconsistent card and draws four more. If the challenge fails, the challenger draws two cards. o Later in the round: the bluffer takes back the inconsistent card and draws only two more cards (if the challenge fails, the challenger draws just one card). Teacher Notes: • We played several rounds in class before implementing the challenge penalties in order to encourage challenges and discussions. • With the challenges, the goal is to encourage the development of the paragraph proof. As students get used to the game, insist on more complete explanations in a more logical order. • Instead of calling “UNO” when down to their last card, players call “EUCLID”. Two exterior angles add to 270° One exterior angle is 135° All exterior angles are 120° One exterior angle is acute. This triangle has two acute angles. The measures of all angles are integers. sin𝐴 is a rational fraction. tan𝐶 is a rational fraction. sin𝐵 is a rational fraction. Area is an integer Area is 100 𝑐𝑚2 Area is less than 70 𝑐𝑚2 Area is less than 40 𝑐𝑚2 Area is greater than 100 𝑐𝑚2 Area is greater than 20 𝑐𝑚2 No side is longer than 20 cm. No side is shorter than 20 cm. One side of this triangle is twice as long as another side.
February 7, 2026 at 9:15 PM
mathcurmudgeon.bsky.social
Simple Fahrenheit to Centigrade conversions on a calculator.

Life should be more simple.
#Calculators
#PEMDAS
#GEDMAS
5/9x(70-32)=21.111 5/9(70-32)=0.014619883
September 20, 2025 at 1:32 AM
mathcurmudgeon.bsky.social
Nerd-sniped myself this morning:

I found myself wondering if the hypotenuse of one of the triangles ever lined up *exactly* with the leg of another, and if so, which one?
May 17, 2025 at 5:07 PM
mathcurmudgeon.bsky.social
Things my students said today:
"A corner of your cheese landed on my chair." & Massive giggle fit. To her sister: "Take your earpod out of your ear, young lady." More giggles. Drops calc on own foot: "My foot. It's been attacked." Whole class loses it.
#mathstoday
#iteachmath
#YeahItsAlmostSummer
May 13, 2025 at 10:10 PM
Reposted by Math Curmudgeon
joshgondelman.bsky.social
I can't believe we have a Pope from Illinois. People from Chicago usually hate the Cardinals.
May 8, 2025 at 5:51 PM
mathcurmudgeon.bsky.social
Rational Functions, factoring review, operations with algebraic fractions ... all wrapped up into one set of problems, with code-breaking. It's like butttaaah.
#algebra2
#mathstoday
Rational Functions Cipher Puzzle v2 Simplify each expression; match to the answers on the other side. 1. (5x+15)/(x^2-x-20)*(2x-10)/(10x^2+50x+60) 2. 4/(x-5)-(4x+7)/((x+2)(x-5)) 3. (4x^3+12x^2)/(x^2+5x)÷(2x^4+10x^3+12x^2)/(x^3+5x^2-4x-20) 4. 3/(x+2)+1/(x+4) 5. 4/(3(x+4))-(x+2)/(x+4)(x+1) +2/(3(x+1)) 6. (x^4-x^2)/(x+5)*(x^2+3x-10)/(x^4-5x^2+4) Matching. A. 1/(x^2-3x-10) B. 2(x-2)/x C. 2(2x+7)/(x^2+6x+8) D. 1/(x^2+6x+8) E. x^2/(x+2) F. (x+2)/(x^2+5x+4) From the other side, list the answers to create the key to a Vigenére Cipher. Vigenére KEY: ___ ___ ___ ___ ___ ___ Use the coding / decoding tools at http://rumkin.com/tools/cipher to decode the following instructions. For each of the rational functions that follow, write in order (leaving off negative signs) AIOV AE KA IQQI; FHBPLI WO MGYXHRT CSH XSF TTX13 f(x)=(2(x-25)(x+24))/((x-2)(x+24)) f(x)=(21x-315)/(x+18) f(x)=(17x^2+340x-748)/(x^2-3x+2) f(x)=(16x-400)/(x+17) f(x)=(32(x-14)(x-8))/(2(x-8)(x+25)) f(x)=(6x^2+240x+2250)/(x^2+23x+120) f(x)=(24(x^2+4x-12))/(x^2+8x+12)
May 8, 2025 at 6:11 PM
mathcurmudgeon.bsky.social
#NewTeacherAdvice
Small whiteboards, cheap markers (~ $0.10 each) are well worth the math department investment.
view of classroom table with white boards, markers, and a rational functions simplification problem written on a white board.
May 5, 2025 at 9:17 PM
mathcurmudgeon.bsky.social
#MTBoS #Iteachmath It's time for the occasional reminder of the day in 2021 when I did a Google Image search for "Math Icons". I was looking for images to use on a website menu ... symbols, math class cartoons, and such. Here's a partial screenshot.
IYKYK
google image results for "math icons" Includes a picture of Sam.
April 9, 2025 at 1:51 PM
mathcurmudgeon.bsky.social
Something has changed about the decor in the White House but I just seem to put my finger on it … maybe there’s a bit more orange and gilt?
April 8, 2025 at 1:53 PM
mathcurmudgeon.bsky.social
If you’re going to criticize and/or ridicule the 86 yo president for typos, you should probably run spell check on your own article before publishing.

“allowed”
April 4, 2025 at 2:27 PM
mathcurmudgeon.bsky.social
And you kids said there was never going to be a use for negative numbers in the real world!
Adam Kitzinger tweet says that he now has negative four security clearances after Tulsi Gabbard posts that his clearance has been revoked again.
March 29, 2025 at 6:50 PM
mathcurmudgeon.bsky.social
Another update on a DESMOS file that shows transformations by highlighting points.

Any ideas for improvement?
#iteachmath #mathstoday
www.desmos.com/calculator/s...
ALG2 - Transformations Update
www.desmos.com
March 27, 2025 at 8:49 PM
mathcurmudgeon.bsky.social
If anyone is interested, here's a quick mock-up of how you can show points translating along with translating curves.
#Iteachmath #algebra #MathsToday
www.desmos.com/calculator/k...
ALG2 - Transformations Update
www.desmos.com
March 21, 2025 at 4:15 PM
mathcurmudgeon.bsky.social
Love this visual of the proof of the angle sum theorems in Precalculus. I do it every year and it never fails to amaze.
Horizontally:
Green=yellow-pink
cos(A+B) = cosAcosB-sinAsinB

Vertically:
Yellow = green + pink
sin(A+B) = sinAcosB + sinBcosA
#iteachmath
#MathsToday
Right triangle in a rectangle to show why the angle sum formulas in trigonometry work.
March 14, 2025 at 9:57 PM
mathcurmudgeon.bsky.social
Setting up for the German Tank problem ...
blog.mathmedic.com/post/bring-b...

Counting out and numbering popsicle sticks, la la la, and I end up with 88.

No, wait. The last two just snapped. It's only 86.
Bring Back the German Tanks
Josh Tabor discusses a revised version of the German Tank Problem - an excellent activity for introducing sampling distributions.
blog.mathmedic.com
March 13, 2025 at 5:05 PM
mathcurmudgeon.bsky.social
Hello, World.
Sorry, but this is who the USA is now. A lot of us voted for Harris, but enough people voted for nobody, or sat out, or voted for the iDJT. Half of our Government is fully behind the Orange One, and half of the country LOVES it. Apologies in advance for what we're about to do.
March 5, 2025 at 2:51 AM
mathcurmudgeon.bsky.social
Hey, @cnn.com
When you interview a fired govt worker, it’s fine to focus on that person and the impact on them, but you should also highlight what now isn’t getting done for USA.
Breaking News, Latest News and Videos | CNN
View the latest news and breaking news today for U.S., world, weather, entertainment, politics and health at CNN.com.
cnn.com
February 27, 2025 at 2:08 PM
mathcurmudgeon.bsky.social
In #mathstoday, the alg2s worked on The Problem.
The data in the following table list natural gas consumption ( in quadrillion BTU ) in the United States. Estimate the consumption in 1982, 2000, 2010, & 2016. Natural Gas Consumption Year: 1960 1970 1980 1990 1997 Consumption: 12.4 21.8 20.4 19.3 22.6 Source: US Department of Energy A. Enter the data into a table. Use two-digit years. With only the data appearing on your graph, estimate the numbers for 1983, 2000, 2010, and 2016. a. When you estimate, remember that this is real. Why would natural gas consumption change in the way you think it would? B. Find a polynomial function that models the data. a. Desmos, create a table. Enter the values. b. What order function does that data seem to be following? c. Create a regression. d. What is the equation that seems to match the data best? C. Graph the model and the data together. Take a screenshot. a. How good is the match between the model and the data? b. Use your model (equation) to estimate natural gas consumption in 1982. c. Can we feel confident about the 1982 estimate? Explain why or why not. D. Use your model (equation) to estimate the natural gas consumption in 2000, 2010 and 2016. a. Can we feel comfortable about these estimates? Explain why or why not. How good was your model? Imagine that the 2000, 2010, and 2016 numbers were dramatically different from your model … how different would they have needed to be to make you reconsider and choose a different model in Part B?
February 18, 2025 at 9:20 PM