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ProfSmudge

@profsmudge.bsky.social

School maths should be more than tables and algorithms. I try to write materials that show that. Dietmar Küchemann

362 Followers  |  197 Following  |  792 Posts  |  Joined: 15.11.2024  |  2.1313

Latest posts by profsmudge.bsky.social on Bluesky

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Amazon-speak for
Package was left on doorstep

06.12.2025 17:14 — 👍 0    🔁 0    💬 0    📌 0

Thank you - similar to my initial method, but using ÷6, x6 to give 11 x 10.

06.12.2025 11:19 — 👍 0    🔁 0    💬 0    📌 0

Thank you. When I wrote this I had in mind multiplying the mixed number to turn it into a whole number, like your last method, except I multiplied by 6, giving 11x10. Then other methods came to mind, like some of yours (I didn't see 2x66 – 1/3 of 66 !).
[Also 1&1/3 of 6 =10, so 10+100.]

06.12.2025 11:17 — 👍 1    🔁 0    💬 0    📌 0
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A simpler version, perhaps.

05.12.2025 16:35 — 👍 0    🔁 0    💬 1    📌 0
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Think of ways to solve this

05.12.2025 09:43 — 👍 0    🔁 0    💬 7    📌 0
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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....

04.12.2025 12:22 — 👍 2    🔁 0    💬 0    📌 0

Interesting idea

03.12.2025 08:58 — 👍 1    🔁 0    💬 1    📌 0

Why the music?!

02.12.2025 17:10 — 👍 6    🔁 0    💬 2    📌 0
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Would you choose the same diagram or different diagrams for the two tasks?

02.12.2025 13:33 — 👍 0    🔁 0    💬 0    📌 0

But note also, that we usually draw a double number line with each line representing a particular measure space, in this case people along one line and pizzas along the other. That's the left hand DNL in my example.

02.12.2025 10:35 — 👍 0    🔁 0    💬 0    📌 0

Yes, the numbers form a ratio table. Note also that the 'vertical' or 'between the lines' multiplier is the same for all pairs of numbers, whereas the 'horizontal' or 'along the lines' multiplier is not. If we had 2 pizzas instead of 3, we would still divide by 5 but would multiply by 2/5 not 3/5

02.12.2025 10:33 — 👍 0    🔁 0    💬 1    📌 0
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Actually, this makes A and B more equivalent

01.12.2025 10:32 — 👍 1    🔁 0    💬 1    📌 0
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Which diagram do you prefer here?

01.12.2025 10:19 — 👍 1    🔁 0    💬 1    📌 0

Yes, something like that!
If for example one thinks of the scalar relations (pizzas to pizzas, and people to people), in A these happen 'horizontally' (along the lines), in B they happen 'vertically' (between the lines).

01.12.2025 09:39 — 👍 0    🔁 0    💬 0    📌 0

Thanks Matt. That's mind-boggling! It seems to 'work' even though the interpretation of the numbers doesn't fit their meaning in the story!

29.11.2025 17:25 — 👍 1    🔁 0    💬 1    📌 0
"Ami, go home!" - German Anti-American Song
YouTube video by scryl "Ami, go home!" - German Anti-American Song

Can't help thinking of this. Our new song?!
[Might need to tweak the words a bit.]
www.youtube.com/watch?v=fJbx...

29.11.2025 12:59 — 👍 1    🔁 0    💬 0    📌 0
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Opinions welcome!

29.11.2025 12:47 — 👍 7    🔁 2    💬 7    📌 0
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And we could use Heron's shortest path problem:

28.11.2025 16:56 — 👍 3    🔁 1    💬 1    📌 0

- and for me it didn't click that it formed an ellipse!

28.11.2025 16:10 — 👍 2    🔁 0    💬 1    📌 0

Yes, it's not 100% obvious!
If one moves the top vertex horizontally and further and further away (so obtuse-angled triangle) the perimeter clearly gets bigger and bigger, but that doesn't immediately rule out that the right-angled triangle is a minimum.
What if the isos triangle is made of string?

28.11.2025 13:28 — 👍 2    🔁 0    💬 1    📌 0
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If we slide the top vertex of the triangle on the right leftwards to form the triangle on the left, then the length of the red side increases by more than the length of the green side decreases....
[Because of the angles in the two small triangles sharing the 1 unit horizontal base....]

28.11.2025 11:35 — 👍 3    🔁 0    💬 1    📌 0

Nice task.
Looked at statically it is hard to tell: on the left, the vertical line is shorter than each of those on the right but the slanting line is longer.
Looked at dynamically, it is pretty clear (!) that the closer the top vertex is to the 'middle', the smaller the sum of the sides.

28.11.2025 09:23 — 👍 2    🔁 0    💬 1    📌 0

Ah, I see - quite nice!

26.11.2025 20:49 — 👍 1    🔁 0    💬 0    📌 0

? What's the nice conclusion ?

26.11.2025 20:26 — 👍 0    🔁 0    💬 1    📌 0

Yes, indeed! But it still shows that the small shapes each cover 1/5²

24.11.2025 15:29 — 👍 1    🔁 0    💬 0    📌 0
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- and other possible arrangements of the smaller shape:

24.11.2025 11:19 — 👍 0    🔁 0    💬 1    📌 0
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Or blobs....

24.11.2025 11:17 — 👍 1    🔁 0    💬 3    📌 0
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Wow, thanks. Here's its cousin

23.11.2025 13:25 — 👍 4    🔁 1    💬 1    📌 0
Post image 23.11.2025 11:14 — 👍 13    🔁 3    💬 3    📌 0
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It's nice that NCETM is using our ICCAMS task to clarify their thinking on oracy. But how far should one push the use of formal maths language? Is there not a danger that pushing formal language will work against inclusion?

21.11.2025 13:06 — 👍 1    🔁 0    💬 0    📌 0

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