peterrowlett

peterrowlett, 1 month ago to random

My son: “I’ve spotted a little typo in Kyle’s book. He says natural logarithm, or L N for short, not N L.” #tmwyk

peterrowlett, 1 month ago to random

#Voted Even though they made it quite a trial — they’ve made it you now need to have and remember to take ID, and they’ve moved my polling station a 20-minute walk away from where it’s been for as long as anyone can remember.

peterrowlett, 1 month ago to random

Teachers! When am I ever going to use this? @stecks talks Pythagoras in the real world. This weekend’s New Scientist or on the website. #iTeachMath #MTBoS

peterrowlett, 1 month ago to random

Amusing my son with the fact today’s date is “twenty four twenty-four” #tmwyk

peterrowlett, 2 months ago to random

This morning my son said “I’m trying to work out how many ways there are putting up three fingers” (holding up one hand). I showed him if you put one finger down there are four choices which other finger to put down. Since there are five choices for which you put down first, that makes 5×4=20. Then I showed him that each pair could be put down two ways, so doing this meant we’d counted each pair twice, so the answer is 10. He wanted to know how this works for other numbers, which led us into a conversation involving factorials, which was pretty deep for an 8yo.

Then this afternoon he called me over and said he was trying to use this to work out how many teddy bears he could make. By pattern matching he’d found 8. I explained this was not the same problem because we aren’t choosing any three from six, but have to pick the right body parts. I showed him there are two sets of bears, one with each head. Then there are two sets, one with each body, and the same for legs. So there are 2×2×2=8 bears.

#tmwyk

peterrowlett, 2 months ago to random

Delighted to see George Green's Windmill is getting funding for repairs!

The windmill was owned by mathematical physicist George Green (1793-1841) and built by his father, and has been a working windmill and science centre since it was restored in the 1980s. Alas the sails were removed in 2022 - I took this picture when I visited in January 2024.

Apparently the money will be used for repairs to the sails, machinery and building, and will make the mill fully operational again.
https://www.bbc.co.uk/news/uk-england-nottinghamshire-68658634

peterrowlett, 2 months ago to random

How would you answer this? Use a spoiler warning! I’ll put my 8yo’s method in a reply behind a spoiler.

peterrowlett, 2 months ago to random

Martin Gardner, writing in 1977. Email was already being sent, telegrams had been around forever. I guess what he describes is more like a fax machine than email?

(The article this is introducing is about ciphers to protect such electronic communications, so this is an introductory sideline.)

peterrowlett, 3 months ago to random

My 8yo: What’s 2 times pi?

Me: Well pi is three-and-a-bit, so 2 times pi would be six-and-a-bit.

Him: Six and two bits.

Me: Yes. Six and a bigger bit.

Him: Can you think of a number in the pi times table that’s a whole number?

#tmwyk

peterrowlett, 3 months ago to random

I agreed to run a primary school ‘maths puzzles and games’ club for years 4-6. So I have a bag of bits and I’m off to run the first session on Noughts and Crosses variants. Wish me luck!

peterrowlett, 4 months ago to random

I set my 8yo working out 18×17 on the walk to school, to demonstrate to him that he is good at multiplication even if he can’t score full marks when school test him on his times tables. School want him to recall anything from 1×1 to 12×12 in six seconds, and to do 25 of these in a row with three seconds gap between each. He has some memorised, and can work out the rest correctly but not always in six seconds.

18×17: He split 17 into 10+5+2, then worked out 10 18s is 180, half that is 90, and double 18 is 36, then added 180+90=270 and added on the 36 for 306. He was very excited and proud, and we talked about how this is a good skill to have, even if it isn’t what’s being tested in the times table test.

#tmwyk

peterrowlett, 4 months ago to random

New paper, free to read #openaccess

I solve a problem about coincidence, but really it's about problem solving and bakes in some stuff about mathematical thinking, creativity, and communication.

https://scholarship.claremont.edu/cgi/viewcontent.cgi?article=2033&context=jhm #iTeachMath #MTBoS

peterrowlett, 4 months ago to random

My son decided to spend some time before breakfast playing Dobble. He said “I’m testing the Dobble theory”. He explained he was checking that each pair of cards had one symbol in common, and that there were no three cards which all share the same symbol. 1/2

peterrowlett, 5 months ago to random

Play the 2024 game!

peterrowlett, 5 months ago to random

My son read this page of Short Cuts: Maths yesterday. This evening I asked him why can’t you? He said “if you ask a mathematician what’s the square root of 4, they’ll say plus 2 or minus 2.” He was a little unclear on why -2 times -2 is 4.

Then he looked thoughtful and said “what’s the square root of minus 4?”

I said “Ah, that’s a good question”. He giggled and said “I know, it’s i 4. I read about it in an earlier chapter.”

I told him that it’s 4i, but you don’t learn that until university. He was extremely chuffed.

#tmwyk

peterrowlett, 5 months ago to random

Get some maths in your Secret Santa planning!

(Or: watch an illustration of zero-knowledge protocols using a Christmas context!)

https://youtu.be/ehRTbNIr6-E

peterrowlett, 5 months ago to random

A year ago today Twitter started preventing links to Mastodon, meaning I got an error when I tried to link to my Mathstodon profile.
https://x.com/peterrowlett/status/1603758546465816579

Ban ended a few days later, but was fun while it lasted.
https://x.com/peterrowlett/status/1604758678556798977

peterrowlett, 5 months ago to random

My son has got to the logic chapter of Short Cuts: Maths.

“Another barber could shave them!”

#tmwyk

peterrowlett, 6 months ago to random

“Daddy, what’s an uncountably infinite busload?”

“Oh, didn’t it explain what an uncountable infinity is?”

“Yes, but what’s a busload?”

#tmwyk

peterrowlett, 6 months ago to random

A story about primes which starts in a Finite Group livestream and ends in the OEIS.

Primes, reversals and concatenations
https://aperiodical.com/2023/11/primes-reversals-and-concatenations/

peterrowlett, 6 months ago to random

We’re playing Noughts and Crosses variants in Game Theory and Recreational Mathematics this morning. What’s your favourite Noughts and Crosses variant?

peterrowlett, 6 months ago to random

A couple of weeks ago @stecks, @sam_hartburn, @alisonkiddle and I got together and signed a limited number of copies of Short Cuts: Maths. You can buy one here:

https://mathsgear.co.uk/collections/books/products/short-cuts-maths-navigate-your-way-through-the-big-ideas-signed-hardback

peterrowlett, 6 months ago to random

I teach a module 'Game Theory and Recreational Mathematics'. Via giving the G4G talk today* on game theory, I just heard about Stanley Eigen's Northeastern University course 'Math, Magic, Games & Puzzles':
https://news.northeastern.edu/2023/11/02/magazine/math-magic-tricks/

• https://www.gathering4gardner.org/com-2023-11-21/

peterrowlett, 6 months ago to random

We did a Finite Group livestream this evening. @stecks showed me some interesting prime number maths, and I showed her a coding thing.

Comments in the chat at the end included “Thanks great job”, “Thanks, that was fun!” and “Thank you, I enjoyed that”. So that’s nice!

If you sign up soon, you’ll get access to view the recording of the session! http://finitegroup.co.uk/

peterrowlett, 6 months ago to random

Day 2 at @BigMathsJam. Yesterday I gave a talk, ran an evening activity, signed 35 copies of Short Cuts: Maths, and signed some Christmas cards to send to Finite Group members (sign up now to get one!). A more restful day today! #mathsjam