My best guess is that the teacher would call a student up to the board, and then (using some sort of semi-random process, like slapping a ruler against the board) use the wheel to generate a problem for the student to solve (5x7, or 8x9). It looks like a more complex/extensible version of this worksheet: https://www.superteacherworksheets.com/multiplication/circle...
I'm 27 years old from West Africa.
2 is always even. 3 only gets to 30 after 3 x 10. 4 has a quick pattern (4>8>2>6>0>..). 5 always ends in a 5 or a 0.
7's pattern is long 7>4>1>8>5>2>9>6>3>0>.. with no sense to it and the numbers get big fast.
8's pattern is short (8>6>4>2>0>..) but the numbers are unwieldy getting into the 40s really quickly.
9's pattern is easy: start with 09. Add one to tens-place and subtract one from ones-place. So it's long, but pretty: 9>8>7>6>5>4>3>2>1>0>..
I skipped 6 because it seems to me that 6 would probably be pretty difficult for the same reason 8 is difficult. Its pattern is short (6>2>8>4>0>..) but there's less sense to it than there is to 8's pattern, and the numbers get large rather quickly.
At least, that's the reasoning I've always figured. I have no idea.
UK: eggs come in 6s. Pizzas get cut into 4s and perhaps 8s for a really huge one, so multiples of those numbers get seen around. Half is sort of easy (all my adult students can usually find half of a figure, especially if I encourage them to think of paying it out in money with £10 notes and £1 coins). 5 fits into the decimal system nicely. Threes are easy to count up.
Days of the week?
But just thinking around weeks, apart from a fortnight do you actually count the days in multiples of 7 or just think about months or a period of weeks?
American football scores.
3's multiples' digits always add up to a multiple of three. So 69 is 6+9 which is 18, a multiple of three.
9's multiples' digits always add up to a multiple of nine. So 108 is 1+0+8 which is 9, a multiple of 9.
6's multiples' digits are always even and add up to a multiple of three.
I've been using the script for all of my handwriting for over a decade, even filling out cursive-prohibited official forms without issue. The swift transition from being notorious for "Dr.'s handwriting" to being sought after to fill out wedding and funeral cards was startling.
Maybe a stupid question but, how? I have pretty horrible handwriting, certainly doctor level; how did you manage a swift transition?
My writing became stylised in my teens, as I'm sure is true with many others. It sloped backwards, and I used a Greek style e and d, purely out of aesthetic reasons.
In my adult life I noticed this made my writing really slow. This became a problem when I sat some exams in adulthood: my hand cramped as I tried to scrawl as fast as possible in the time limit.
I deliberately investigated faster, more comfortable writing styles. Internet consensus, which I note agree with, indicated that joined-up, forward-leaning (italic) cursive was the way to go. The saw-tooth shape that underpins most letters is easy and feels natural -- if you're right handed.
It took me about 6 months of deliberate effort before the transition was fully embedded, and I'm still very pleased that I made the change.
People interested in how penmanship has changed over the 20th century might be interested in this (weirdly expensive book)
My grandfather grew up in the rural Midwest and wrote with a very attractive calligraphic style a bit closer to Spencerian; my dad still does too.
This one is not beautiful at all, in my opinion:
This one (low res) is very well aligned, but e's and s's aren't too good: https://twitter.com/OKCPS/status/606905034111000576/photo/1
I do know that my niece and nephew had to have my mom's letters to them read to them by my sister as the schools they attended never taught cursive
Penmanship is one failing I keep trying to remedy, I think a lot can be communicated through it besides the words a letter may contain
"Hey, we have $120,000 to spend. Make it happen." I would then go to the different section chiefs and ask what they needed as spares. Some were reasonable requests, others were ridiculous. If we didn't spend the money, the budget would decrease the next year, and it would be hell getting that money back when a really expensive part died.
The hilarious thing is that the Inspector General's office is responsible for preventing this thing from happening... but if you go talk to their requisitions personnel around September, they're doing the exact same shit as everyone else.
Don't ask me to explain it, but it's true.
The comment you replied to is saying the boards that covered up these "time-capsule" boards have been used for 100 years. :)
So, presumably, the "old chalkboards" being removed by contractors have been there since 1917, or approximately 100 years.
I've been wondering how often would a regular teacher make such elaborate drawings. Considering this completely arbitrary and small sample, I guess the answer is "often".
edit - added 3rd citation
Monday was later adopted internationally (and there is an ISO  for which is the first day of the week too) for business reasons, as it's the first office work begins again, banks open, etc in most places.
I once booked a flight on the wrong day because part way through the booking process the first day of the week in the calendar changed.
Nursery rhymes with this order: http://en.m.wikipedia.org/wiki/Monday%27s_Child
Chinese use 星期一 / "weekday one" for Monday.
Well... it's true that Chinese generally consider Monday the beginning of the week, but that's not evidence. The days of the week are 一 (1)、二 (2)、三 (3)、四 (4)、五 (5)、六 (6) and 天 or 日 (day). Does day come before 1 or after 6 when you count?
edit: the map lower down in the thread ( https://en.wikipedia.org/wiki/Week#/media/File:First_Day_of_... ) shows China as beginning its week on Sunday. That does not agree with my experience, or with the Chinese people I've asked this question of.
Sure, Monday through Saturday are numbered 1 to 6, but Sunday is "weekday Sky" or "weekday Heaven", which is considered to come before "weekday one".
Interestingly, there's no first day: Saturday and Sunday are sábado and domingo, respectively.
- That map is factually incorrect. Sunday is considered the end of the week in China, not the beginning. I note in passing that the image file is attributed to "own work" -- we all make mistakes.
- The 天 of 星期天 doesn't have the sense of "sky" or "heaven". It has the sense (well, originally had the sense) of "day", the unit of time. Compare 天天 "every day"; 今天 "today"; 明天 "tomorrow". We know that this is the original sense because the name descends from the Christian term 礼拜天 "the day of worship". Consider also that 周天 alternates with 周日, and while 日 shares the sense "day" it does not share the sense "sky".
When we hear that in other countries Sunday is considered the first day of the week, sounds almost as weird as being told that they consider "z" to be the first letter of the alphabet.
Also, it is very frustrating when a UI uses Sunday as the first day of the week, and I encounter that quite often.
> it's true that Chinese generally consider Monday the beginning of the week
My cousin comment responds to the claim that you can tell China begins the week on Monday because its name is "week one", 星期一. That claim is problematic; China does begin the week on Monday, but the name doesn't prove so.
Monday is the first day.