Scathing Atheist 512 Script
Added 2022-12-08 04:14:02 +0000 UTCBecause Heath just can't stop putting visual aids in the notes.
Comments
That's weird, my Android tablet spells it "Wolfram Alpha"
Myk the tango-dancing skeptic
2022-12-08 14:38:06 +0000 UTCAlso, at Eli's question, it doesn't work with 81. Quite obviously, since the digits of 81 don't add up to 81 :D I don't know of a smarter shortcut than actually dividing by 9 and then checking if the result is divisible by 9. And for Noah, a fun fact, this is a trick that works with all bases! The principle is that if the digits in base X add up to something divisible by X-1, then the whole thing is divisible by X-1. So to check if a number in hexadecimal (base 16) is divisible by 15, you add up all digits and check if the result is divisible by 15. For example 0x555 in hex is 1365 in decimal, and 1365/15=91
V0ldek
2022-12-08 13:37:20 +0000 UTCI shouldn't be surprised at this point that Eli pronounces Wolphram Alpha as "wolfstram alpha", but still. Damn.
V0ldek
2022-12-08 13:28:50 +0000 UTCEli, as a math teacher I really liked and was intrigued by your thought that the divisibility rules for 3 & 9 might indicate that those rules scale to other powers of 3. My understanding is that it doesn't so much relate to powers of 3, but more to 3 & 9's relationship to 10. Since 10 is the base of our number system, it relates strongly to the digits in a number. Also, these rules are limited to only applying to single digit numbers, because they have to apply to any number (integer). Since every number (integer) will at least have a "ones" digit, these divisibility rules mostly stay with single digits. Anyways, if you or anyone else is interested Khan Academy has a pretty good explanation https://youtu.be/NehkLV77ITk
Kendallyn Frost
2022-12-08 07:24:29 +0000 UTC
