>>On the 1st day of Xmas, my true love gave to me:
>>1 item
>>On the 2nd day of Xmas, my true love gave to me:
>>2 items + 1 item
>>On the 3rd day of Xmas, my true love gave to me:
>>3 items + 2 items + 1 item
>>.
>>.
>>On the n-1 day of Xmas, my true love gave to me:
>>n-1 items + n-2 items + ... + 1 item
>>On the nth day of Xmas, my true love gave to me:
>>n items + n-1 items + ... + 1 item
>>
>>How many total items did my true love give to me, as a function of n?
>
>Number of gifts = gifts(n)
>
>

>FUNCTION gifts(n)
>lnReturn = 0
>FOR I = 1 TO n
>  FOR H = 1 TO I
>    lnReturn = lnReturn + H
>  ENDFOR
>ENDFOR
>RETURN lnReturn
>

>
>not arithmetic, but it works

Er, yes, but there is an elegant mathematical solution that even a computer would like! (no looping involved)