My Problem With 7

My reposted problem of a couple days ago, about building all the digits of a clock face using exactly three 9’s and simple arithmetic combinations of them, caught in my mind, as these things will sometimes do. The original page missed out on a couple ways of using exactly three 9’s to make a 1, but it’s easy to do. The first thing to wonder about was how big a number could we make using exactly three 9’s? There must be some limit; it’d be absurd to think that we could make absolutely any positive integer with so primitive a tool set — surely 19,686 is out of the realm of attainability — but where is it?

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Reblog: Ummm… What time is it?

Math 4 Most put up a lovely little challenge here, to find a typo in a novelty clock face. As usual for this sort of novelty clock face the various expressions come out to the familiar old 1, 2, 3, et cetera up through 12; so, can you spot one (or more than one) that doesn’t come out right?

Every couple years someone in my family buys me one of the mathematical-puzzle calendars, where there’s a bit of arithmetic to work out for each day. (For example, something for today might ask the square root of 196, although dressed up to be more interesting.) It’s good mental practice working through it, the equivalent of doing the daily Jumble word puzzle or a Sudoku problem. I admit I’m more inclined to the Jumble since I like many of the wrong words that come up in trying to unscramble ‘Object’ and ‘Recipe’. (Those are the words causing more more trouble than any in the common Jumble vocabulary.)

Math 4 Most

Funny Math Clock
Can you find the typo?!

As I troll through the web, I often wander through sites that have some pretty humorous math related content.  When I find some I’d like to share, I’ll add them to this page.  I will try to keep whatever I post to the PG level at most.  (Yes there is risqué math, who knew!?)

NOTE: I do not own nor imply ownership of any images I find on the web.  Whenever possible, I will provide info on the rightful owner.  If you discover a picture/link which I have incorrectly attributed, please let me know!

This picture has been going around Facebook for a while… but it has a typo!! Do you see it?

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