Although lcm() works in Maxima... it won't work for me in Smath using Maxima(lcm())
I'm a noob but researched for hours and am non-the-wiser... Any help is much appreciated.

The only result when searching the forum is a Matlab plugin which I couldn't work... plus I'm not sure lcm() is included with that plugin anyway.
https://en.smath.info/forum/yaf_postst1970_Matlab-C-Math-Library.aspx

lcm.sm (2.73 KiB) downloaded 542 time(s).

You need to load the "functs" package in Maxima first. Seems that wxMaxima does that on startup. I could also load this package automatically if required.
You can add this locally to your maxima.xml in the plugin directory (search for this file to find the directory).

Thank you Mr. Kraska...

I found a Japanese page where others had to load it on their Maxima first as well.
http://web.sfc.keio.ac.jp/~yama/nos/?p=3505

Also this third party Maxima manual tells users to do so as well.
http://www.delorie.com/gnu/docs/maxima/maxima_95.html

Which turned out to actually be the instructions for SMath not Maxima.
Now I suppose I'll need to write a loop in order to use the function with more than two numbers.
Somewhat curious since Maxima has an ezgcd() function which accepts more than two inputs. Anyhow, I will click thanks on your profile Sir.

update: When I click thank on your post an error occurs.