Logic and Maths problems (HS RELATED)



So every once in a while I shall post a logic or maths problem for you guys to solve.

This is hopscotch related because it will develop our thinking and this will help improve the thinking that goes into making the wonderful projects on HS.

Here is one I did in school today:

1: Take any three different digits for example 352
2: then repeat that number to make a new 6 digit number 352352

This number will always be divisible by 7, 11 and 13

Try it with three digits....does it work?
If yes then can you explain why?

This is really fun to do! Apparently it will always work...
Can anyone prove me wrong?


List (88 tags)



That's a cool little math trick! :stuck_out_tongue:


This topic is kinda like this one


Sorry, but these are just fun challenges...


Can anyone fix the hide details thing?


Yeah, if you put it on wiki


Sorry I don't know how to do that :confounded::confounded::confounded::confounded:



_ u dont know how cuz ur not regular
U will be soon!


I think it's always going to beds devils lettuce by 7, 11 and 13


Can you figured out why?


Yay @StarryDream thanks for making a #trendygirl tag!


You're welcolm!
I also have da #starrydream tag and #starrydreamwashere(made by @minioncandy) and #starrysfrenswashere(made by me) and #rainboomvsstarry(made by @Rainboom)


I'm not regular :sob:
I can't make tags.


Juuust you wait :3333


I figured it out! :smiley: Hint: Multiply those three numbers and see if you notice a pattern.
Here's another similar puzzle that you can solve without much math at all:
Take any prime above 3. p2-1 always divisible by 24. Why?


Okay I have one

X/3 = 5/6
Solve for X

<cough2 1/2 cough>


Hmmm.... I'm not sure... maybe... two and one half...?


Awesome! I know this trick! It works because 7 * 11 * 13 equals 1001. That means, this trick only works with 3-digit numbers.