Countdown Numbers
#1
Posted 2008-September-11, 22:40
100 25 10 8 7 5 = 804
#2 Guest_Jlall_*
Posted 2008-September-11, 23:27
The 7 made it tricky (to me).
#5
Posted 2008-September-11, 23:45
matmat, on Sep 11 2008, 10:41 PM, said:
I spent quite a bit of time under this assumption before realising that it is impossible...
Jlall said:
#6
Posted 2008-September-11, 23:47
matmat, on Sep 12 2008, 12:41 AM, said:
how about
(100-25-8) * (10+7-5)
#7 Guest_Jlall_*
Posted 2008-September-11, 23:50
matmat, on Sep 12 2008, 12:47 AM, said:
matmat, on Sep 12 2008, 12:41 AM, said:
how about
(100-25-8) * (10+7-5)
I like, but not quite in order right? I was assuming they didnt have to stay in order.
#8 Guest_Jlall_*
Posted 2008-September-11, 23:53
#9
Posted 2008-September-11, 23:54
Jlall, on Sep 12 2008, 12:53 AM, said:
i'm still trying to get them in order :/
#10
Posted 2008-September-12, 00:05
In that sense (100-25-8)*(7+5) is the simplest solution. How easily gettable that is within the 30 seconds allowed is debatable.
Probably the easiest solution to find quickly is 100*8+7-(25+5)/10 or 100*8+7-(25-10)/5, but under time pressure it's easy to panic and think you "obviously" can't make 3 with 25,10 and 5.
#11
Posted 2008-September-12, 00:11
sceptic, on Sep 11 2008, 11:05 PM, said:
It is pretty easy to get 803 and 805 in less than 30 seconds..
#12 Guest_Jlall_*
Posted 2008-September-12, 00:15
EricK, on Sep 12 2008, 01:05 AM, said:
oh, that makes it easier.
#13
Posted 2008-September-12, 00:42
#14
Posted 2008-September-12, 08:10
sheepman, on Sep 12 2008, 05:40 AM, said:
100 25 10 8 7 5 = 804
7-(25-10)/5+8*100
Wasn't timing, didn't feel like 30 seconds though
#15
Posted 2008-September-12, 11:10
If you're reasonably facile with numbers, but not especially so, you should find that a few solutions kind of just jump out at you, some others can be solved in the 30 seconds, many you can get an answer close to the one wanted, and a few just leave you scratching your head!
Contestants in the TV program usually get some credit for getting close to the right answer (within 10 I think) provided their opponent doesn't get closer.
Nick

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