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Math Curmudgeon @mathcurmudgeon.bsky.social · 20/09/2026

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

matharguments.com

The Consistency Game

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Math Curmudgeon @mathcurmudgeon.bsky.social · 31/08/2026

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

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Math Curmudgeon @mathcurmudgeon.bsky.social · 15/07/2026

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

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Math Curmudgeon @mathcurmudgeon.bsky.social · 21/04/2026

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

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Math Curmudgeon @mathcurmudgeon.bsky.social · 22/03/2026

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

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Math Curmudgeon @mathcurmudgeon.bsky.social · 13/03/2026

#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...

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Math Curmudgeon @mathcurmudgeon.bsky.social · 10/03/2026

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...

drive.google.com

Consistency - Google Drive

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Math Curmudgeon @mathcurmudgeon.bsky.social · 07/02/2026

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.

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.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 20/09/2025

Simple Fahrenheit to Centigrade conversions on a calculator. Life should be more simple. #Calculators #PEMDAS #GEDMAS

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Math Curmudgeon @mathcurmudgeon.bsky.social · 17/05/2025

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?

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Math Curmudgeon @mathcurmudgeon.bsky.social · 13/05/2025

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

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Reposted by Math Curmudgeon

Josh Gondelman @joshgondelman.bsky.social · 08/05/2025

I can't believe we have a Pope from Illinois. People from Chicago usually hate the Cardinals.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 08/05/2025

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)

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Math Curmudgeon @mathcurmudgeon.bsky.social · 05/05/2025

#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.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 09/04/2025

#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.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 08/04/2025

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?

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Math Curmudgeon @mathcurmudgeon.bsky.social · 04/04/2025

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”

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Math Curmudgeon @mathcurmudgeon.bsky.social · 29/03/2025

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.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 27/03/2025

Another update on a DESMOS file that shows transformations by highlighting points. Any ideas for improvement? #iteachmath #mathstoday www.desmos.com/calculator/s...

desmos.com

ALG2 - Transformations Update

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Math Curmudgeon @mathcurmudgeon.bsky.social · 21/03/2025

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...

desmos.com

ALG2 - Transformations Update

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Math Curmudgeon @mathcurmudgeon.bsky.social · 14/03/2025

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.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 13/03/2025

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.

blog.mathmedic.com

Bring Back the German Tanks

Josh Tabor discusses a revised version of the German Tank Problem - an excellent activity for introducing sampling distributions.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 05/03/2025

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.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 27/02/2025

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.

cnn.com

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.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 13/02/2025

In #MathsToday. The box announces that Cologuard finds 92% of colon cancers. Later in the ad, we're told false positives can occur & this slide flashes on the screen. If you receive a positive result, what are the chances that you do have colon cancer?

Cologuard advertisement.
Banner says "In a clinical study, 13% of people without cancer received a positive result (false positive) and 8% of people with cancer received a negative result (false negative)

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Math Curmudgeon @mathcurmudgeon.bsky.social · 10/02/2025

Four more for today.

$Disrespectful bear cub for adding fractions incorectly$ Disappointed puppy for misusing the distributive property.

Evil raccoon enjoys your mistake with radicals (surds, if you're British)

Math unicorn has its feelings hurt when you screw up your square root operations: r(4) + r(6) = r(10)

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Math Curmudgeon @mathcurmudgeon.bsky.social · 07/02/2025

I feel this needs more exposure ...

Cartoon: Ozymandius statue but the face on the head is Elon Musk, and the inscription reads "so much mighy wow ... mega(?) rich how money"

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Math Curmudgeon @mathcurmudgeon.bsky.social · 07/02/2025

Time trolls trump today, Musk at the #ResoluteDesk. Which is the greater fool? #TimeMagazine

Time magazine cover with elon musk behind the resolute desk.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 04/02/2025

I out together this quick demonstration of what multiple roots at a point look like to help my students understand how there can be more than one root at a point. www.desmos.com/calculator/h... #MathsToday #iteachmath #Algebra2 #Thesearefunbuthardtoread #ThatsBetter

DESMOS screen grab of a quartic polynomial and its roots.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 01/02/2025

Our Class 4 road in Vermont. Sometimes it’s tough getting to school.

Our road, class 4, covered in snow and sorta plowed.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 01/02/2025

In an executive order signed this morning (31 Jan 2025), @realDonaldTrump required all public schools to cease using both the Greek and Latin alphabet. “Only the American alphabet.” In a separate order, pi was changed to p and set equal to 3. #executiveOrders #Potus47

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Math Curmudgeon @mathcurmudgeon.bsky.social · 27/01/2025

Elon wants to call his committee, “DOGE”, but I think we should call it DOG-E, pronounced “doggie”, instead.

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benjamin dickman @benjamindickman.bsky.social · 27/12/2024

fascinating list! cc #iTeachMath ♾️ #EduSky ☁️ i found myself agreeing with all the odd claims and disagreeing with the evens. or vice-versa, i can no longer recall...

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Math Curmudgeon @mathcurmudgeon.bsky.social · 24/12/2024

Have a wheelie Merry Christmas and Happy New Year.

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Math Curmudgeon @mathcurmudgeon.bsky.social · 18/12/2024

#iteachmath #mathstoday Every year I give my students the December Puzzle series. Here are the next four

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