That my daughter, who is 43, has had grapheme-colour synaesthesia since she was small. She never mentioned it to us before. She said that it's great for spotting errors in spreadsheets, but not what you'd put in your CV.
One of my many children has this. I found out one day when he was about 8 or 9 and told us that 2 is orange, and was quite bemused that we didn’t all see numbers etc like this. He doesn’t really mention it much (he’s 16 now) so I’m not sure how it effects his day to day life. I’ll have to question him again soon. One day. Maybe.
One of my hiking club mates also has this, extends beyond numbers so Left and Right are Red and Green in such order that the colours of port and starboard when transposed to shoes are the wrong way round for her, says it's a bit stressful when things don't match her perception.
The full article is here! https://mainichi.jp/english/articles/20200821/p2a/00m/0bu/025000c
Apparently Japan is running out of credit card numbers with the COVID-driven shift from cash to credit cards.
Since the population is less than 120 million, how do larger countries cope?
Urgh, <digs into memory> nope but here's a better explanation from "how stuff works"
https://money.howstuffworks.com/personal-finance/debt-management/credit-card1.htm---
The first digit in your credit-card number signifies the system:
3 - travel/entertainment cards (such as American Express and Diners Club)
4 - Visa
5 - MasterCard
6 - Discover Card
The structure of the card number varies by system. For example, American Express card numbers start with 37; Carte Blanche and Diners Club with 38.
American Express - Digits three and four are type and currency, digits five through 11 are the account number, digits 12 through 14 are the card number within the account and digit 15 is a check digit.
Visa - Digits two through six are the bank number, digits seven through 12 or seven through 15 are the account number and digit 13 or 16 is a check digit.
MasterCard - Digits two and three, two through four, two through five or two through six are the bank number (depending on whether digit two is a 1, 2, 3 or other). The digits after the bank number up through digit 15 are the account number, and digit 16 is a check digit.
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The issuers have their own way of allocating bank numbers, so presumably the problem is they are running out themselves rather than the system.
Actually Wikipaedoia have another descruiption that's in more depth
https://en.wikipedia.org/wiki/Payment_card_numberAlso the UK allocator of PANs and IINs
https://www.wearepay.uk/what-we-do/standards/iin/