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2018-12-31, 19:40   #1
Batalov

"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

3×3,061 Posts
2019 number games

https://www.theguardian.com/science/...019-in-numbers

Quote:
 Originally Posted by Ed Southall 2019 is the smallest number that can be written in 6 ways as the sum of the squares of 3 primes: 7² + 11² + 43² = 2019 7² + 17² + 41² = 2019 13² + 13² + 41² = 2019 11² + 23² + 37² = 2019 17² + 19² + 37² = 2019 23² + 23² + 31² = 2019
Date jam

1. Using only the digits 2, 0, 1 and 9, create expressions that equal all of the numbers from 0 to 12.
The expressions can include any of the arithmetical symbols +, –, x, ÷ and √, and brackets.

I’ll start you off:

0 x (2 + 1 + 9) = 0
2 – 1 + (0 x 9) = 1
Note: you must use each of the digits 2, 0, 1 and 9 once and only once in each expression.

Happy New Year!

2018-12-31, 20:02   #2
petrw1
1976 Toyota Corona years forever!

"Wayne"
Nov 2006

32·7·71 Posts

Quote:
 Originally Posted by Batalov 1. Using only the digits 2, 0, 1 and 9, create expressions that equal all of the numbers from 0 to 12. The expressions can include any of the arithmetical symbols +, –, x, ÷ and √, and brackets. I’ll start you off: 0 x (2 + 1 + 9) = 0 2 – 1 + (0 x 9) = 1 Note: you must use each of the digits 2, 0, 1 and 9 once and only once in each expression. ...and read on. Happy New Year!
(9+1)*0+2=2

NEXT...

2018-12-31, 20:10   #3
science_man_88

"Forget I exist"
Jul 2009
Dumbassville

26×131 Posts

Quote:
 Originally Posted by Batalov https://www.theguardian.com/science/...019-in-numbers Then, the rather traditional -- Date jam 1. Using only the digits 2, 0, 1 and 9, create expressions that equal all of the numbers from 0 to 12. The expressions can include any of the arithmetical symbols +, –, x, ÷ and √, and brackets. I’ll start you off: 0 x (2 + 1 + 9) = 0 2 – 1 + (0 x 9) = 1 Note: you must use each of the digits 2, 0, 1 and 9 once and only once in each expression. ...and read on. Happy New Year!
2=2+(0*1*9)
3=2+1+(0*9)
4=(9-1)/2+0
5=(9+1)/2+0
6=9-2-1-0
7=9-2+(1*0)
8=9-1+(2*0)
9=9+(1*2*0)
10=9+1+(2*0)
11=9+2+(1*0)
12=9+2+1+0
16=(9-1)*2+0
17=9*2-1+0
18=9*2+(1*0)
19=9*2+1+0
20=(9+1)*2+0
27=9*(2+1+0)

just a few guesses.

 2018-12-31, 20:29 #4 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 32×7×71 Posts Dates in 2019 that are All Primes DISCLAIMER: Standard Date format where I work is: YYYYMMDD. Dates in 2019 that are prime in all regards. That is, all the following are prime numbers. YYYYMMDD YYYY MM DD MMDD 20190523 20190719 20191117 If you include YYYYMM then only the last 2 numbers above qualify. This is the only date for which ONLY YYYYMMDD is prime: 20191027 I retired (for the first time) on a date like this in 2011 (20110523) https://www.mersenneforum.org/showthread.php?t=15616 Interestingly May, 23 is also prime in 2019. Must be a sign? Time to retire again? Last fiddled with by petrw1 on 2018-12-31 at 20:39

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