To explain forum code tags, you can use the HTML code tag:
[s]strikethrough[/s]
Everything encoded in <code> … </code> tags will be rendered “as is” without interpretation by the forum software.
Oh, and if you use HTML entities to render the “less than” and “greater than” characters when writing an HTML tag, this also prevents the tag being interpreted. The entities in question are written as follows:
& lt; is the "less than" character
& gt; is the “greater than” character
Omit the space after the ampersand to generate the entity.
Indeed, you can render all manner of characters this way, so that the following set of HTML entities:
& alpha; & beta; & gamma;
& Alpha; & Beta; & Gamma;
renders the Greek characters as follows:
α β γ
Α Β Γ
There’s a vast list of HTML entities understood within HTML (works for HTML 4 and 5), which have both numerical code designation and named designations. For example, this lot:
& planck; & int; & part;
Renders the following symbols:
ℏ ∫ ∂
The full list can be found here, but that list is rendered in a stupidly small font, and you need to use an accessibility magnifier to view it properly (sigh). A more readable set is this one.
Enjoy!