Paddy MacMahon
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Paddy MacMahon
@paddymacmahon.com
1.2K followers 440 following 1.7K posts
Head of Maths at Latymer Upper School
paddymacmahon.com
OCR, Cambridge International and AQA associate, Desmos and Google Colab enthusiast
Posts Replies Media Videos
paddymacmahon.com
Anyone else have requests for discretionary entries to BMO1 from external candidates? I haven't ever had any before, and this year I've had half a dozen. I've refused our own candidates who missed the cut by more than a couple of marks a discretionary entry...

@ukmathstrust.bsky.social
#Mathstoday
November 19, 2025 at 10:48 PM
Reposted by Paddy MacMahon
chalkdustmag.bsky.social
🦂🚨🦂 New Chalkdust alert! 🦂🚨🦂

DNA origami, tracks and an interview with El Nombre feature in our AW25 issue! Plus all your favourite puzzles & columns.

Read the entire new issue now at
chalkdustmagazine.com
Chalkdust: Read Issue 22 now
A magazine for the mathematically curious. Issue 22 now available: DNA origami, tracks and an interview with El Nombre feature in our AW25 issue! Plus all your favourite puzzles & columns.
chalkdustmagazine.com
November 17, 2025 at 11:24 AM
paddymacmahon.com
Wonderful stuff! Thanks for sharing!
benjamindickman.bsky.social benjamin dickman @benjamindickman.bsky.social · 9d
new NEW @cshor.org pset 🥳

🔗:
drive.google.com/file/d/1mk6R...

alt text:
Screenshots of pages 1, 2, 3, and 7 (first three & last)

I haven't even read the problems but I cosign/cosine them nevertheless

#iTeachMath ♾️ #MathSky 🧮
November 16, 2025 at 7:40 PM
Reposted by Paddy MacMahon
mathforge.org
Sunday night seems the right time to post a gallery of (I hope!) every one of Catriona's geometry puzzles.

notes.mathforge.org/notes/publis...

Give it a moment to load ... there's a *lot* of them!

#GeometryPuzzles #UKMathsChat #mathsky
Puzzle Gallery in Notes
notes.mathforge.org
November 16, 2025 at 6:24 PM
paddymacmahon.com
Ordered!
jameshandscombe.bsky.social James Handscombe @jameshandscombe.bsky.social · 12d
Exciting times - I now have a copy of my book!
November 10, 2025 at 3:51 PM
paddymacmahon.com
Things I discovered today when comparing the take-home-pay spreadsheets we built in #CoreMaths with the gov.uk calculator: www.gov.uk/estimate-inc...

Unlike Income Tax, National Insurance is paid on my gross salary rather than my post-pension-contributions salary;
Estimate your Income Tax for the current year
Estimate how much Income Tax and National Insurance you can expect to pay for the current tax year (6 April 2025 to 5 April 2026).
www.gov.uk
November 7, 2025 at 12:33 PM
Reposted by Paddy MacMahon
tombutton.bsky.social
Next term we'll be running a version of our popular 'Maths into Data Science and AI' course for non-A level Maths students.

This 9-session online course is ideal for students of Core Maths or A level Computer Science.

You can sign your students up now at: amsp.org.uk/event/b08828...
A data scientist pointing at a graph on a screen
November 3, 2025 at 9:26 AM
Reposted by Paddy MacMahon
ridermeister.bsky.social
@ukmathstrust.bsky.social are here!

#MathsToday #AlevelMaths #UKMathsChat
October 29, 2025 at 1:25 PM
paddymacmahon.com
#MathsToday #ALevelMaths

Away for half term for the last couple of weeks... but here's today's Monday Area Problem.

Find the exact value of the green area.
The curve y=x² is in red. Two normals, at points in the second quadrant, intersect eachother at a point on the curve in the first quadrant with y-coordinate 3. The area enclosed by the curve and the two normals is shaded green.
November 3, 2025 at 6:26 PM
paddymacmahon.com
And... half term. Early start on Sunday morning, taking 50 pupils to Uganda!
October 17, 2025 at 2:47 PM
paddymacmahon.com
Looks interesting!

#MathsToday

euromathsoc.org/news/ems-lec...
The European Mathematical Society is thrilled to announce its Lecture Series on Mathematics Education uniting leading experts to explore critical issues and innovative approaches in mathematics teaching, curriculum design, and policy making. These engaging one-hour webinars will occur on the second Friday of each month from January to June 2026 at 7:00 PM CET and will be moderated by Tom Crawford.
euromathsoc.org
October 16, 2025 at 6:34 AM
Reposted by Paddy MacMahon
mathforge.org
The Oxgordshire Youth Maths Conference was fantastic - but then I would say that, so here's Helen saying it so you can believe it!

#MathsToday #UKMathsChat

PS if you're in a secondary school in Oxfordshire, let me know if you're interested in attending next year.
headingtonhelen.bsky.social Headington Helen @headingtonhelen.bsky.social · Oct 15
Huge thanks to @mathforge.org for organising the inaugural Oxfordshire Youth Maths Conference this week. Our 6 students who participated loved it and my colleague who took them said it was just right-- superb presentations by the students, not too long and the right number of breaks. Congrats!
October 15, 2025 at 6:00 AM
paddymacmahon.com
#MathsToday #ALevelMaths #FurtherMaths

Find the exact value of the green area.
The graphs of y = a/x³ and y = a - x³ are in red. They share a mutual tangent point in the first quadrant. The area enclosed by the x-axis and the two curves, with no upper limit, is shaded green.
October 13, 2025 at 5:16 PM
Reposted by Paddy MacMahon
stevemaths.bsky.social
Here's our #OCRMathsPuzzle to end this week. 🙂

The vertices of a square just touch four edges of a regular octagon, as below.
The area of the square is 32 cm^2.

Work out the area of the regular octagon.

#MathsToday #UKMathsChat #RecreationalMath #geometry #area
Image describes the geometric problem. The vertices of a square just touch four edges of a regular octagon. The area of the square is 32 cm squared. Work out the area of the regular octagon.
October 10, 2025 at 2:03 PM
paddymacmahon.com
Maclaurin Series in #ALevelMaths #FurtherMaths #MathsToday, so we're building animations using @desmos.com. Here's my effort:

www.desmos.com/calculator/z...
maclaurin animator
www.desmos.com
October 10, 2025 at 11:33 AM
paddymacmahon.com
A bonus area problem for the end of the week, inspired by a post by @mrlevmaths.bsky.social.

Important info from the alt-text: the curve is a parabola.

#ALevelMaths #MathsToday
paddymacmahon.com Paddy MacMahon @paddymacmahon.com · Oct 9
I saw your labels and thought these represented the actual areas (as in the area of region 1 is 1 unit, of region 2 is 2 units, etc...) which got me thinking that that sort of thing might make a nice problem. Impossible to get regions with those areas using a parabola, but I came up with this:
A parabola passing through the origin and a positive value on the x-axis, with a maximum point in the first quadrant. A straight line with positive gradient intersects the parabola at 2 points in the first quadrant. Vertical line segments are drawn from each of these intersection points to the x-axis, so the area enclosed by the parabola and the x-axis is divided into 4 regions. The left hand region has area 13, the right hand region has area 44 and the top region has area 8. The final region is labelled with a question mark.
October 9, 2025 at 6:09 PM
Reposted by Paddy MacMahon
peterrowlett.net
The call for peer reviewers is very real - if you teach maths at the upper end of school through to early university and are interested in maths content useful to people like you, please get in touch via [email protected] - thanks!

#MathsToday #UKMathsChat #ALevelMaths #MathToday #MathSky
October 8, 2025 at 5:23 PM
Reposted by Paddy MacMahon
catrionaagg.bsky.social
In #MathsToday I made 40 A Level teachers colour in representations of the binomial distribution.

This is your regular reminder that if you teach #ALevelMaths you should definitely try to join your local Maths Hub’s A Level Pedagogy group. There is some brilliant stuff going on all over England.
A quartet of representations of the binomial distributions. Screenshots from https://www.desmos.com/calculator/3ea50eafbc X ~B (10, 0.4) Shade the diagrams to represent the probability P(3 ≤X <6) and draw a numberline. X~B(10,0.4) Shade the diagrams to represent the probability P(3 ≤ X < 6) and draw a numberline. X ~ B(8, 0.7) Which is larger: P(X < 5) or P(X = 6)? X~B(12,0.36) P(X ≥ c) < 0.5 What is the smallest possible value of c? X~B(10,0.4) Calculate the interquartile range of this distribution. What is the mode? X~B(8, 0.7) P(X ≤ a) < 0.1 What is the largest possible value of a? P(X ≥ b) < 0.1 What is the smallest possible value of b? X~B(12,0.36) P(X ≤ a) < 0.2 What is the largest possible value of a? P(X ≥ b) < 0.2 What is the smallest possible value of b?
October 8, 2025 at 8:18 PM
paddymacmahon.com
Lots of SMC practice in #MathsToday.
October 8, 2025 at 10:10 AM
Reposted by Paddy MacMahon
jedediyah.com
First @NCTM.org yearbook (1926) here: catalog.hathitrust.org/Record/00006...

An interesting take on quadratics!

"Nor should we expect to have all the pupils able to factor ax^2+bx+c (a useless accomplishment for most people)"

"If the subject is to be valuable, the learning should be a pleasure"
As a result of this view of the reason for teaching algebra, we have come to see that we should not expect everyone to solve two simultaneous quadratic equations, although out of an entire class there will be found a few who can do so. Nor should we expect to have all the pupils able to factor ax^2+bx+c (a useless accomplishment for most people), a considerable number will take pleasure in performing such a task and will thereby acquire some special skill which they may find useful in later work. The purpose of teaching algebra is found in none of these details: it consists in giving to everyone a general idea of the meaning of algebra, together with a few definite and useful applications which everyone is likely to meet. If the subject is to be valuable, the learning should be a pleasure, and it may properly be expected that this pleasure will carry the pupil into such manipulations of algebraic expressions as will fix the habit of using algebra in the cases to which it can be applied.
October 6, 2025 at 9:22 PM
Reposted by Paddy MacMahon
drkatedevlin.bsky.social
Am off to Kraków soon for a talk on Thursday as part of @unsoundfestival.bsky.social — awesome music festival (with talking bits too). www.unsound.pl/en/unsound-w...
Kate Devlin IDISCOURSE PROGRAMME] 09.10 13:15 Patac Krzysztofory - Sala Miedziana Discussion: Future Sex unsound. [web] 7-12October Kraków
October 6, 2025 at 9:35 PM
Reposted by Paddy MacMahon
meimaths.bsky.social
We are proud to be sponsoring 10 places to attend the teacher day at ICTMT17 in London on 22 Oct buff.ly/piLruty

Take part in workshops, meet sector leaders, hear MEI’s Tom Button & Natalie Vernon on using Desmos

Apply: buff.ly/mnzr2N5

#ICTMT17 #MathsEd
October 6, 2025 at 9:15 AM
paddymacmahon.com
#ALevelMaths #MathsToday

Monday area problem. Find the exact value of the green area.
The graph of y=x² is in red, together with the point (sqrt3 / 2, 3/4) highlighted and labelled in blue. Also in red is a circle, tangent to the x-axis and touching the curve at the blue point. The region enclosed by the curve, the circle and the x-axis is shaded green.
October 6, 2025 at 5:34 AM
paddymacmahon.com
Very proud of our girls in #MathsToday. 19 distinctions and 19 merits in the UKMT Mathematical Competition for Girls.
October 3, 2025 at 7:58 AM
Reposted by Paddy MacMahon
darrenmacey.bsky.social
For more ideas for teaching statistics, check out our new lesson activities designed for Maths Week Scotland. rss.org.uk/resources/ed...

#MathsWeekScot
October 2, 2025 at 4:15 PM