Friday, June 29, 2018

number theory - Divisibility by 37 proof



¯abc is divisible by 37. Prove that ¯bca and ¯cab are also divisible by 37.



¯abc=100a+10b+c
¯bca=100b+10c+a
¯cab=100c+10a+b
When you add them:
¯abc+¯bca+¯cab=111a+111b+111c

¯abc+¯bca+¯cab=111(a+b+c)
Since 111 is divisible by 37, the whole sum is divisible by 37, but how can i prove that ¯abc, ¯bca, ¯cab separately are divisible by 37?



Any tips or hints appreciated.


Answer



¯bca=10¯abc1000a+a=10¯abc2737a


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