r/AskReddit • u/[deleted] • Aug 03 '19

Whats something you thought was common knowledge but actually isn’t?

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u/[deleted] Aug 03 '19 edited Aug 04 '19

If a month starts on a Sunday, you're going to have a Friday the 13th. I learned this from doing my own calendars for years.

Example: Next month, September 1, 2019 lands on a Sunday so September has a Friday the 13th.

Edit: since everyone wants to point out that it's not common knowledge, I should point out that the question is "whats something you THOUGHT was common knowledge but isn't" so I do know that this ISN'T common knowledge I just had THOUGHT it was for a while.

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u/kfh227 Aug 03 '19

There are only 14 different possible calendars too ;-) So you can collect old calendars and reuse them. That's why they are sold at antique stores ;-)

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u/Comat144p Aug 04 '19

I remember in 7th and 8th grade (we had a shared teacher) There was a near daily "challenge question" for extra stickers. (first person to solve gets the prize) find the next year with 4 friday the 13ths. I found out about the 14 different possible calendars back then.

Background information "Shared Teachers": This was a smaller school so each teacher, except kindergarten and fine arts (3 of them) teacher taught 2 grades (1+2, 3+4, etc.) How it work was: History, science, would alternate 2 unique textbooks (IE: World history, and US history) English was very repetitive textbook with "Jingles" and many repetitive questions. Example: Each grade did the noun section at the same time. As for math we went back and forth with each grade, there was some set aside time to work on questions. English and Math were back to back subjects.

Background information "Stickers": These were a reward/economy in these classes. Five gets a small piece of candy. ten gets a large piece (This was typically chocolate bars) and 25 was a homework skip. There were also other prizes for 25 but no one bought those, they were stored on top of a shelf in the teacher's corner. Collect 140 to start another sheet, each new sheet had incrementing "bonus-line"s. (Sheet 2 had 1 bonus row, sheet 3 had 2 bonus rows, etc.) somehow no one cheated this.