#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.
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
@loke@peterrowlett I'd say today is the twentieth of the fourth, twenty-four, so I don't think Swedish is that different. Peter just skipped some words to make it better 😉
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.
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.
My son’s answer. He said he thought about the single digit squares and they are 1, 3 and 9. He knew it couldn’t be zero or two because there aren’t zero- or two-sided shapes. So he checked 72 is in the 8s times table. Clearly he didn’t need the factors bit, I wonder if this is intended as part of the knowledge needed for that question, but it did reassure him his answer was correct. #tmwyk
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 I wonder how common computers with live displays instead of teletype printers were in 1977. I suppose even if people were using personal computers with CRT displays, it would still feel more reasonable to read a letter in paper than on a screen
@christianp@peterrowlett The TRS-80 came out in 1977. I think up to then kit home microcomputers like the Altair 8800 might well have had only a teletype. And only a very niche hobby rather than commonplace.
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!
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.
I solve a problem about coincidence, but really it's about problem solving and bakes in some stuff about mathematical thinking, creativity, and communication.
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