666
Usage: {{User:Saintrain/A/NegTest|SomeNumericString}}
.
This template attempts to evaluate the numeric string.
So:
{{NegTest|100 -1}}
(using a hyphen) returns 99;
{{NegTest|100 −2}}
(using a markup minus) returns 98;
{{NegTest|100 −3}}
(using a literal minus) returns 97.