iiinova — where your digital self keeps evolving

John Rubinstein @jrub.bsky.social · 01/10/2026

Would you get your answer from the normal approximation? Or use the normal approx to get a rough answer and then check with the actual binomial to get the accurate answer?

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John Rubinstein @jrub.bsky.social · 26/09/2026

Came across this quote today from St Augustine: “The good Christian should beware the mathematician and all those who make empty promises. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of hell.”

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John Rubinstein @jrub.bsky.social · 24/09/2026

Does anyone teach row reduction as a method for finding the inverse of a 3x3 matrix? This is the method I was brought up with (SMP A level maths many years ago). It is never mentioned in specs and mark schemes but I assume it’s an acceptable method? #ALevelMaths #FurtherMaths

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John Rubinstein @jrub.bsky.social · 22/09/2026

I was cycling to work this morning and as I came to a crossroads, I noticed another cyclist coming toward me on the other side. He waited at the red light and then set off when it turned green. I make a habit of writing down rare or notable events.

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John Rubinstein @jrub.bsky.social · 22/09/2026

As you are clearly an expert, can you adjudicate a 30-year argument for me please? If I make a sandwich using two slices of bread and some filling, and I cut it (diagonally, obvs), have I got one sandwich cut in two, or two sandwiches?

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John Rubinstein @jrub.bsky.social · 16/09/2026

Why has Piddington declared itself a principality? Doesn’t it need a prince for that?

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John Rubinstein @jrub.bsky.social · 16/09/2026

I love it too, especially when I walk away from school halfway through the day.

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John Rubinstein @jrub.bsky.social · 03/09/2026

I thought you couldn’t take FM2 unless you took FM1. For example, I don’t think you are allowed to take FS1 with FM2. Am I wrong?

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John Rubinstein @jrub.bsky.social · 02/09/2026

So do I, they are fun to teach. But some years, 70% of the marks for FM1 go to collisions/impulse, which seems a bit OTT to me. I would love FM1 students to do a bit of SHM and/or circular motion instead of so much collisions.

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John Rubinstein @jrub.bsky.social · 01/09/2026

Sainsbury up to £34 now and Amazon £29.

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John Rubinstein @jrub.bsky.social · 01/09/2026

Has anyone researched the latest ‘best place to buy calculators’ before I do? #ALevelMaths

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John Rubinstein @jrub.bsky.social · 01/09/2026

I remember Luton As I’m eating my crouton

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John Rubinstein @jrub.bsky.social · 01/09/2026

I think FM1 is terrible! There is far too much collisions, totally unbalanced. But FM2 is excellent. When Edexcel put me in charge, I will redistribute topics between FM1 and 2, put oblique impact into FM2 and bring circular motion in FM1.

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John Rubinstein @jrub.bsky.social · 25/08/2026

Anyone around north London can teach A level maths for a few days at an outstanding sixth form college in Harrow on the Hill? Their results were fab, and they are massively over subscribed and maths numbers are bouncing ... I taught there three years myself, brilliant place to teach. #ALevelMaths

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John Rubinstein @jrub.bsky.social · 16/08/2026

Interesting that AQA maths is much higher numbers than OCR but lower in Further Maths. I wonder why.

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John Rubinstein @jrub.bsky.social · 14/08/2026

Ours are 20 and 19, and 9 for further

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John Rubinstein @jrub.bsky.social · 13/08/2026

(Slight exaggeration but I take your point)

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John Rubinstein @jrub.bsky.social · 13/08/2026

Imperial college maths school had 88% A*-A and the same size cohort as Michaela (60 students in Y13). They have 10 going to Oxbridge (and 14 to Imperial).

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John Rubinstein @jrub.bsky.social · 13/08/2026

Maybe. You might prefer Imperial wherever you are in the UK. I still think two is a bit low for such impressive results. I’m thinking maybe they have been well drilled to pass A levels but less well prepared for entrance tests and/or interviews.

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John Rubinstein @jrub.bsky.social · 13/08/2026

Okay, about the same size as my sixth form.

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John Rubinstein @jrub.bsky.social · 13/08/2026

Michaela School got 70% of A level grades at A or A*. That’s double the rate at my school. But Michaela only got two students into Oxbridge, same as my school, and I’m sure their sixth form must be bigger. So, why only two?

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John Rubinstein @jrub.bsky.social · 13/08/2026

BBC are reporting the regional gap in A Level results, saying it’s a post code lottery, that some students are doing worse just because of where they live, implying some regions just have worse schools. Surely that’s facile. The regional differences are driven by demographic differences.

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John Rubinstein @jrub.bsky.social · 21/07/2026

But that means fewer take English. So we need to try to get more boys to take English and humanities subjects. 2/2

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John Rubinstein @jrub.bsky.social · 21/07/2026

I think also there is a factor in the fall in English which relates to the rise of female students taking STEM subjects. It is positive that more girls opt for subjects traditionally thought to be more the male preserve, and we get more female doctors, engineers, scientists. 1/2

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John Rubinstein @jrub.bsky.social · 21/07/2026

Lucy Powell 2 Esther Phillipson 0

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John Rubinstein @jrub.bsky.social · 19/07/2026

Yes good Q. I also wonder if the Y12 is fully taken into account in UCAS offers. For example if the general offer is A*AA, does an A* in Y12 knock it down to AA or do they need A*AA in the three remaining Y13 A levels?

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John Rubinstein @jrub.bsky.social · 19/07/2026

Our students take the actual A level at the end of Y12. It’s the first school I ever worked which does this. I am still not sure if I agree with it or not. But they all get A or A* at the end of Y12.

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John Rubinstein @jrub.bsky.social · 10/07/2026

We have ten lessons a week. We finish the syllabus before Easter. Last three years every student got A or A* in their A level maths at the end of Y12.

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John Rubinstein @jrub.bsky.social · 10/07/2026

Our FM students have grades 7-9 in maths GCSE. We have around 8 or 9 of them. Apart from FM we have two sets of single maths, about 19-20 in each.

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John Rubinstein @jrub.bsky.social · 10/07/2026

It probably doesn’t help much to say so, but the sensible thing is to teach the FM students separately for both maths and further maths, and then you can develop a logical order that doesn’t impact on single maths students. In my school, FM students cover the whole AL maths in Y12 and FM in Y13.

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John Rubinstein @jrub.bsky.social · 02/07/2026

Email comes from a Year 13 A level maths student who is on holiday abroad somewhere. Not quite sure how to answer …

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John Rubinstein @jrub.bsky.social · 01/07/2026

This is very good. Too many teachers still use z-scores in these tests, which is now unnecessary and opaque given that calculators can now find p-values or critical regions using the sampling distribution.

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John Rubinstein @jrub.bsky.social · 01/07/2026

This is a bit misleading. In maths schools, students have to do both maths and further maths. So to require at least a grade 8 in GCSE maths is not out of line with many schools which also require an 8 to do further maths.

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John Rubinstein @jrub.bsky.social · 01/07/2026

@hcsstweets.bsky.social Do you know: have City done enough business to avoid the points deduction?

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John Rubinstein @jrub.bsky.social · 22/06/2026

What are O-level AMath prelims?

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John Rubinstein @jrub.bsky.social · 20/06/2026

Totally pub quiz. That one was very tough!

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John Rubinstein @jrub.bsky.social · 19/06/2026

So, Edexcel paper 3 looks reasonable. A bit weird that they specified vertical resolving in the inclined plane question (an ‘or otherwise’ would have been nice) but overall no complaints. Some students say the stats was harder and some say the mechanics, and that’s a good sign.

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John Rubinstein @jrub.bsky.social · 19/06/2026

My new favourite LDS question: What is the modal value of daily rainfall in Jacksonville in 1987? #ALevelMaths

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John Rubinstein @jrub.bsky.social · 13/06/2026

The very next question in the same paper requires integration by parts.

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John Rubinstein @jrub.bsky.social · 13/06/2026

See what you think of this question from 2023

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John Rubinstein @jrub.bsky.social · 13/06/2026

Firstly it is erratic in terms of difficulty, sometimes very straightforward but other times extremely challenging - last couple of years especially. Secondly the questions seem written by people more interested in pure maths than genuinely in stats. Thirdly, the crossover stuff with GCSE is boring.

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