[Nottingham] A numerical puzzle & "mathomatic"

Martin martin at ml1.co.uk
Mon Jan 18 11:10:48 UTC 2010

Camilo Mesias wrote:
> It doesn't need that much brute force because the equation is so
> limited. The a+b+c bit appears twice and they are single digits. If n
> is a+b+c we can figure n is between 0 and 27, and n^2 + n is a three
> digit number. We have to start at n=10 to get a three digit result
> (110) but those digits don't add up to 10...
> n=11 (132)...
> n=12 (156) bingo
> just as well because my times tables run out there!

Very good and well deduced.

Thinking further about trying for an algebra solution... There isn't one
in that all that any manipulation can do is either rearrange the formula
or just prove an identity.

At least it prompted a brief look at the "Mathomatic" program which
turned out to be rather neat. Hope I haven't spoilt anyone's homework!

Thanks for that,


Martin Lomas
martin at ml1.co.uk

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