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#tmwyk

3 posts3 participants0 posts today
Continued thread
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Peter Rowlett

He also wrote out the times table to 9x9 and added the entries to get 2025. Here he was very taken that we could get the row sum for 2 by doubling the row sum for 1, then add these together to get the sum for 3, and so on.

#tmwyk
Continued thread
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Peter Rowlett

I was quite taken with this one: 2025 is the product of the proper divisors of its square root, 45.

My son showed me how at school they’d make a factor bug to find the factors 1, 3, 5, 9, 15 and 45, then we worked out 1×3=3, 3×5=15, 15×15 we did as 10×15 plus half as much again to get 225. Finally he did 225×9 by doing 225×10 and subtracting 225.

Child’s drawing of an insect with six legs labelled 1, 3, 5, 9, 15 and 45.
#tmwyk
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Christian Lawson-Perfect

My daughter got a board game from a relative, which wasn't much cop really, but we've had some great maths chat with the leftover packaging.

We had these 2×3 grids. I showed her how you can make a pattern with eight holes by putting two grids on top of each other.

I asked which numbers we can make. We did multiples of 2, then I asked if we could make an odd number. Are there any numbers we can't make?

A 2×4 grid made by putting one grid on top of another, offset by one space.
Four 2×3 cardboard grids
A shape with ten holes, made by putting one grid on another, offset by one space horizontally and one space vertically.
#tmwyk
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Colin the Mathmo

I've been thinking about this for ages, but never had the time to craft the words around it.

People keep saying that "Maths should be fun" ... and I push back with "It should be engaging ... 'fun' is a different thing.

So @rakhichawla has posted pretty much exactly this, but better than I ever could.

I'm copying it here with permission.

Please read this, then as it says at the end ... let's have a deeper conversation about this ...

1/n

(PS: I'd love this to get boosted to get outside my bubble ... you're all amazing, but there will be other opinions, and other thoughts that could be helpful or valuable)

Hashtags:

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Brent Yorgey

I found 7yo drawing on a sheet of paper. He had drawn 8 dots in a circle and was drawing lines between all possible pairs of dots. I told him it was called K8 (and showed him how to write the 8 as a subscript). He thought that was cool and labelled his drawing. I then asked him to draw K3,K2,K1, and K0. He did not even hesitate at K0 but gleefully wrote K0 labelling a blank part of the paper.

He then wanted to draw K10 but I told him it would take too long (we had to leave shortly). I tried to explain something about how the number of lines grew quadratically, though not in those words of course. "Oh yeah," he said, "like how K8 has eight times seven lines." He double counted them, of course, but I was impressed he thought of a way to count them at all.

Looks like we have another budding mathematician on our hands!

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Colin the Mathmo

Some time ago ... (A month!) ... there was a thread on Twitter that I think should be shared here. I've been trying to extract and post it semi-automatically, but Twitter just makes it damn near impossible.

So I'm copying it "by hand"

Here's a chart of the full conversation:

solipsys.co.uk/Chartter/185675

Here's the head of the conversation:

x.com/TweetingCynical/status/1





I will occasionally update the chart of *this* conversation, and it will be here:

solipsys.co.uk/Chartodon/Teach

Here is the content ...

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Peter Rowlett

My son answered a maths worksheet question earlier. It said ‘Sam’ used this method to find a prime factorisation:
18=2x9=2x3x3
Then it asked you to use Sam’s method to answer some questions.

The first question was 36. He did this:
36=2x18=2x9x9=…

Somehow he saw 9 as made of 3s and 18 as made of 9s. An interesting mistake!

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