CalcDemo demonstrates one possible usage of my Ignore404 patch. When you request a page in this group that does not exist, the PageNotFound page will run a phpinc plugin that calculates a number based on the page name.

Currently, it understands page names that consist of two integer numbers combined with one of these operators: plus, minus, times (multiplication) and over (division). Due to PmWiki's page name restrictions, the left number cannot be negative.

About CalcDemo - About the Patch
Examples: 2 plus 3, 8 minus 1, 3 times 5, 12 over 4, 11 over 9, 5 minus -10, 1 times -4