ProfSmudge
@profsmudge.bsky.social
School maths should be more than tables and algorithms. I try to write materials that show that. Dietmar Küchemann
#MathsToday
Counting matchsticks by matching in pairs
Counting matchsticks by matching in pairs
January 14, 2026 at 1:11 PM
#MathsToday
Counting matchsticks by matching in pairs
Counting matchsticks by matching in pairs
London today.
If you think the sun rises in the East and sinks in the West, think again!
If you think the sun rises in the East and sinks in the West, think again!
January 11, 2026 at 10:52 AM
London today.
If you think the sun rises in the East and sinks in the West, think again!
If you think the sun rises in the East and sinks in the West, think again!
Man City owned by the Abu Dhabi royal family, Exeter City owned by its supporters. Sad.
January 11, 2026 at 10:32 AM
Man City owned by the Abu Dhabi royal family, Exeter City owned by its supporters. Sad.
This was taken on Wednesday, 15 minutes before sunrise. How is it that the moon is already 'pointing upwards'?
January 10, 2026 at 8:45 AM
This was taken on Wednesday, 15 minutes before sunrise. How is it that the moon is already 'pointing upwards'?
In #MathsToday we tried to solve this pair of mis-transcribed 'simultaneous equations':
4x + 4 = 14
3x – 4 = 14.
So 7x = 28, so x = 4.
[It seems to me we need to radically rethink the content of GCSE maths and how we teach it!]
4x + 4 = 14
3x – 4 = 14.
So 7x = 28, so x = 4.
[It seems to me we need to radically rethink the content of GCSE maths and how we teach it!]
January 8, 2026 at 12:13 PM
In #MathsToday we tried to solve this pair of mis-transcribed 'simultaneous equations':
4x + 4 = 14
3x – 4 = 14.
So 7x = 28, so x = 4.
[It seems to me we need to radically rethink the content of GCSE maths and how we teach it!]
4x + 4 = 14
3x – 4 = 14.
So 7x = 28, so x = 4.
[It seems to me we need to radically rethink the content of GCSE maths and how we teach it!]
December 29, 2025 at 5:30 PM
That took me a while to understand...
December 29, 2025 at 10:01 AM
That took me a while to understand...
This came to me in a dream. Oh well!
December 26, 2025 at 12:06 PM
This came to me in a dream. Oh well!
How come it costs €1.20 to send a card from Germany, but £3.20 to send one back?!
December 23, 2025 at 12:32 PM
How come it costs €1.20 to send a card from Germany, but £3.20 to send one back?!
Clusters of mistletoe have suddenly appeared on our apple tree...
December 22, 2025 at 10:51 AM
Clusters of mistletoe have suddenly appeared on our apple tree...
#MathsToday Used this task with a group of Y10 students. They struggled to view the task structurally, even when their arithmetic produced the result 241.
But they gained some insight with 7x12 – 6x12.
But they gained some insight with 7x12 – 6x12.
December 18, 2025 at 2:36 PM
#MathsToday Used this task with a group of Y10 students. They struggled to view the task structurally, even when their arithmetic produced the result 241.
But they gained some insight with 7x12 – 6x12.
But they gained some insight with 7x12 – 6x12.
Just received my copy of MT 298, with my article on mathematical thinking
December 11, 2025 at 5:45 PM
Just received my copy of MT 298, with my article on mathematical thinking
#MathsToday Memories of Pythagoras
A Y11 pupil tells me he saw a video about Pythagoras' Theorem with diagrams like these:
A Y11 pupil tells me he saw a video about Pythagoras' Theorem with diagrams like these:
December 11, 2025 at 9:34 AM
#MathsToday Memories of Pythagoras
A Y11 pupil tells me he saw a video about Pythagoras' Theorem with diagrams like these:
A Y11 pupil tells me he saw a video about Pythagoras' Theorem with diagrams like these:
interesting thought? - as it rotates, what happens to the length of the segment through the centre of the pentagon that cuts the pentagon in two?
December 9, 2025 at 9:46 AM
interesting thought? - as it rotates, what happens to the length of the segment through the centre of the pentagon that cuts the pentagon in two?
Does this make sense?
If only 2% give , what use is a donation of £2.75?
If only 2% give , what use is a donation of £2.75?
December 7, 2025 at 7:59 PM
Does this make sense?
If only 2% give , what use is a donation of £2.75?
If only 2% give , what use is a donation of £2.75?
I don't think the fault lies with Bill Posters. All the rest seems to line up.
December 7, 2025 at 7:46 PM
I don't think the fault lies with Bill Posters. All the rest seems to line up.
Amazon-speak for
Package was left on doorstep
Package was left on doorstep
December 6, 2025 at 5:14 PM
Amazon-speak for
Package was left on doorstep
Package was left on doorstep
Think of ways to solve this
December 5, 2025 at 9:43 AM
Think of ways to solve this
In #MathsToday
Varying an expression and thinking about what happens to its value;
and when that didn't work, varying the expression to be varied....
Varying an expression and thinking about what happens to its value;
and when that didn't work, varying the expression to be varied....
December 4, 2025 at 12:23 PM
In #MathsToday
Varying an expression and thinking about what happens to its value;
and when that didn't work, varying the expression to be varied....
Varying an expression and thinking about what happens to its value;
and when that didn't work, varying the expression to be varied....
Can't help thinking of this. Our new song?!
[Might need to tweak the words a bit.]
www.youtube.com/watch?v=fJbx...
[Might need to tweak the words a bit.]
www.youtube.com/watch?v=fJbx...
"Ami, go home!" - German Anti-American Song
YouTube video by scryl
www.youtube.com
November 29, 2025 at 12:59 PM
Can't help thinking of this. Our new song?!
[Might need to tweak the words a bit.]
www.youtube.com/watch?v=fJbx...
[Might need to tweak the words a bit.]
www.youtube.com/watch?v=fJbx...
Opinions welcome!
November 29, 2025 at 12:47 PM
Opinions welcome!
What do we call the tax that you have to pay? Unfair tax?
November 20, 2025 at 12:47 PM
What do we call the tax that you have to pay? Unfair tax?
In #MathsToday yesterday, a Y11 student wondered whether y = 4x + 14 would be the equation of a line parallel to the line with equation y = 2x + 7.
[Where might that have come from? Could one class it as an 'intuition'?]
[Where might that have come from? Could one class it as an 'intuition'?]
November 20, 2025 at 12:05 PM
In #MathsToday yesterday, a Y11 student wondered whether y = 4x + 14 would be the equation of a line parallel to the line with equation y = 2x + 7.
[Where might that have come from? Could one class it as an 'intuition'?]
[Where might that have come from? Could one class it as an 'intuition'?]