▲ 1265 ▼ Panik (i.postimg.cc) submitted 2 years ago by ickplant@lemmy.world to c/lemmyshitpost@lemmy.world 146 comments fedilink hide all child comments
[–] beckerist@lemmy.world 16 points 2 years ago (1 child) 7 is double the last number and subtract from the rest 749 (easily divisible by 7 but for example sake) 9*2=18 74-18=56 6*2=12 5-12= -7, or if you recognize 56 is 7*8... I'll do another, random 6 digit number appear! 59271 1*2=2 5927-2=5925 5*2=10 592-10=582 2*2=4 58-4=54, or not divisible I guess for this to work you should at least know the first 10 times tables... permalink fedilink source parent hideshow 2 child comments replies: [–] logicbomb@lemmy.world 18 points 2 years ago (3 children) Another way to tell if 59271 is divisible by 7 is to divide it by 7. It will take about the same amount of time as the trick you're presenting, and then you'll already have the result. permalink fedilink source parent hideshow 6 child comments replies: [–] tigeruppercut@lemmy.zip 5 points 2 years ago (1 child) But at least I seems like you could do that trick in your head permalink fedilink source parent hideshow 2 child comments replies: [–] logicbomb@lemmy.world 4 points 2 years ago If you have no interest in the result of the division, then you can also do the division in your head, without retaining the result, with about the same effort. permalink fedilink source parent [+] beckerist@lemmy.world 1 point 2 years ago* [deleted] permalink fedilink source parent [+] beckerist@lemmy.world 1 point 2 years ago [deleted] permalink fedilink source parent
[–] logicbomb@lemmy.world 18 points 2 years ago (3 children) Another way to tell if 59271 is divisible by 7 is to divide it by 7. It will take about the same amount of time as the trick you're presenting, and then you'll already have the result. permalink fedilink source parent hideshow 6 child comments replies: [–] tigeruppercut@lemmy.zip 5 points 2 years ago (1 child) But at least I seems like you could do that trick in your head permalink fedilink source parent hideshow 2 child comments replies: [–] logicbomb@lemmy.world 4 points 2 years ago If you have no interest in the result of the division, then you can also do the division in your head, without retaining the result, with about the same effort. permalink fedilink source parent [+] beckerist@lemmy.world 1 point 2 years ago* [deleted] permalink fedilink source parent [+] beckerist@lemmy.world 1 point 2 years ago [deleted] permalink fedilink source parent
[–] tigeruppercut@lemmy.zip 5 points 2 years ago (1 child) But at least I seems like you could do that trick in your head permalink fedilink source parent hideshow 2 child comments replies: [–] logicbomb@lemmy.world 4 points 2 years ago If you have no interest in the result of the division, then you can also do the division in your head, without retaining the result, with about the same effort. permalink fedilink source parent
[–] logicbomb@lemmy.world 4 points 2 years ago If you have no interest in the result of the division, then you can also do the division in your head, without retaining the result, with about the same effort. permalink fedilink source parent
