John Rubinstein
@jrub.bsky.social
Teacher of A level maths and further maths. Ex-principal of a sixth form college. Now a Londoner but still loyal to Hull.
I recommend this movie. Thrilling and funny and entertaining. And incredible soundtrack.
September 29, 2025 at 6:44 PM
I recommend this movie. Thrilling and funny and entertaining. And incredible soundtrack.
I am stuck if any kind soul can help. In the Edexcel Core 1 chapter on roots of polynomials Ex4C Q9, you end up with these four equations, which I haven’t been able to solve.
Solution bank just ‘spots’ the solution, which isn’t very satisfactory.
#ALevelMaths
Solution bank just ‘spots’ the solution, which isn’t very satisfactory.
#ALevelMaths
September 12, 2025 at 8:45 AM
I am stuck if any kind soul can help. In the Edexcel Core 1 chapter on roots of polynomials Ex4C Q9, you end up with these four equations, which I haven’t been able to solve.
Solution bank just ‘spots’ the solution, which isn’t very satisfactory.
#ALevelMaths
Solution bank just ‘spots’ the solution, which isn’t very satisfactory.
#ALevelMaths
If you are at all interested in WW2, in what Britain was like in the late 30s and during the war, in debunking some myths and learning some history, I wholeheartedly recommend this book.
September 10, 2025 at 7:05 PM
If you are at all interested in WW2, in what Britain was like in the late 30s and during the war, in debunking some myths and learning some history, I wholeheartedly recommend this book.
Lots of pleasing mathematical spirals in these plants in a garden in Cornwall.
August 26, 2025 at 9:57 AM
Lots of pleasing mathematical spirals in these plants in a garden in Cornwall.
Just read The Heart’s Invisible Furies by John Boyne. Fantastic. About about a gay boy/man growing up in Ireland in the 50s/60s, later living in Amsterdam and New York before returning to Ireland. So passionate, powerful and moving, but also one of the funniest novels I have ever read.
August 24, 2025 at 6:49 PM
Just read The Heart’s Invisible Furies by John Boyne. Fantastic. About about a gay boy/man growing up in Ireland in the 50s/60s, later living in Amsterdam and New York before returning to Ireland. So passionate, powerful and moving, but also one of the funniest novels I have ever read.
Nice puzzles by Alex Bellos in the Guardian today.
July 26, 2025 at 5:47 AM
Nice puzzles by Alex Bellos in the Guardian today.
I like the one @susanwhitehouse.bsky.social shared the other day. Full version on UM.
July 9, 2025 at 8:36 PM
I like the one @susanwhitehouse.bsky.social shared the other day. Full version on UM.
Here are the answers. And also a practice cryptic crossword which you can use before giving them it as an introduction.
drive.google.com/file/d/1aHoZ...
drive.google.com/file/d/1aHoZ...
July 5, 2025 at 6:24 AM
Here are the answers. And also a practice cryptic crossword which you can use before giving them it as an introduction.
drive.google.com/file/d/1aHoZ...
drive.google.com/file/d/1aHoZ...
I have a problem with this Q from Edexcel Paper 1 #ALevelMaths (I attached the beginning).
1) the result is not true ‘for any number’ but only for integers.
2) you cannot write any squared number as 5n or 5n+1 where n is a natural number. How about 1? That is 5(0) +1 but 0 is not a Nat number.
1) the result is not true ‘for any number’ but only for integers.
2) you cannot write any squared number as 5n or 5n+1 where n is a natural number. How about 1? That is 5(0) +1 but 0 is not a Nat number.
June 12, 2025 at 11:55 AM
I have a problem with this Q from Edexcel Paper 1 #ALevelMaths (I attached the beginning).
1) the result is not true ‘for any number’ but only for integers.
2) you cannot write any squared number as 5n or 5n+1 where n is a natural number. How about 1? That is 5(0) +1 but 0 is not a Nat number.
1) the result is not true ‘for any number’ but only for integers.
2) you cannot write any squared number as 5n or 5n+1 where n is a natural number. How about 1? That is 5(0) +1 but 0 is not a Nat number.
My take on yesterday’s Edexcel Core 1 paper is that it was a fair paper, not too easy, not too hard.
Quite a lot of topics still to come in Core 2.
#AlevelMaths
Quite a lot of topics still to come in Core 2.
#AlevelMaths
May 21, 2025 at 9:39 AM
My take on yesterday’s Edexcel Core 1 paper is that it was a fair paper, not too easy, not too hard.
Quite a lot of topics still to come in Core 2.
#AlevelMaths
Quite a lot of topics still to come in Core 2.
#AlevelMaths
And now the Romanian president too!
May 19, 2025 at 2:38 PM
And now the Romanian president too!
I answered ‘no’ to the @teachertapp.bsky.social question “Do you have a coach at school?” But I think I may have misunderstood the question.
May 11, 2025 at 3:24 PM
I answered ‘no’ to the @teachertapp.bsky.social question “Do you have a coach at school?” But I think I may have misunderstood the question.
Someone posted this question a while back under #AlevelMaths
If you assume that 3 + √2 is also a root, then it’s easy. But can we assume that? Couldn’t it have one root 3 - √2 and two complex conjugate roots?
The question gives the same answer if you don’t make the assumption but longer working.
If you assume that 3 + √2 is also a root, then it’s easy. But can we assume that? Couldn’t it have one root 3 - √2 and two complex conjugate roots?
The question gives the same answer if you don’t make the assumption but longer working.
April 24, 2025 at 12:54 PM
Someone posted this question a while back under #AlevelMaths
If you assume that 3 + √2 is also a root, then it’s easy. But can we assume that? Couldn’t it have one root 3 - √2 and two complex conjugate roots?
The question gives the same answer if you don’t make the assumption but longer working.
If you assume that 3 + √2 is also a root, then it’s easy. But can we assume that? Couldn’t it have one root 3 - √2 and two complex conjugate roots?
The question gives the same answer if you don’t make the assumption but longer working.
As @howiehua.bsky.social would say, here I am: a maths teacher at Harvard.
April 12, 2025 at 9:53 PM
As @howiehua.bsky.social would say, here I am: a maths teacher at Harvard.
Happy Pi Day. At my daughter’s school they had a special Bake Off competition. #MathsToday #ALevelMaths
March 14, 2025 at 1:05 PM
Happy Pi Day. At my daughter’s school they had a special Bake Off competition. #MathsToday #ALevelMaths
A revision activity for Core Pure Further #ALevelMaths.
Any suggestions for any more?
Any suggestions for any more?
March 7, 2025 at 10:23 AM
A revision activity for Core Pure Further #ALevelMaths.
Any suggestions for any more?
Any suggestions for any more?
March 3, 2025 at 12:35 PM
My copy looks like this, but I suspect it’s the same
February 25, 2025 at 9:23 PM
My copy looks like this, but I suspect it’s the same
