This satisfy all requiremts (It must contain a foreach or while command.) (modded from my evil answer to the almost same question)...

WinZ>perl -e " print eval join '+',(1..$ARGV[0]);exit while 1" 13
91
[download]

Serious answer: in some monk's signature there is something like: think a solution without a computer and then translate in our preferred language. for example: I have a Sum, empty for the moment. Then I expand numbers from 1 to GivenNumber (list expansion). Now for each number in the list I add it to Sum. I write down Sum.

HtH
L*