Make numeric increment explicit. Closes #22.

index.md

@@ -49,8 +49,8 @@ However it is done, it should be precise and comprehensive.
 
 1. A normal version number MUST take the form X.Y.Z where X, Y, and Z are
 integers. X is the major version, Y is the minor version, and Z is the patch
-version. Each element MUST increase numerically. For instance: 1.9.0 < 1.10.0
-< 1.11.0.
+version. Each element MUST increase numerically by increments of one. For
+instance: 1.9.0 -> 1.10.0 -> 1.11.0.
 
 1. When a major version number is incremented, the minor version and patch
 version MUST be reset to zero. When a minor version number is incremented, the