@@ -149,6 +149,13 @@
 - (uintmax_t)asUIntMax;
 - (ptrdiff_t)asPtrDiff;
 - (intptr_t)asIntPtr;
 - (float)asFloat;
 - (double)asDouble;
+
+- add: (OFNumber*)num;
+- subtract: (OFNumber*)num;
+- multiplyWith: (OFNumber*)num;
+- divideBy: (OFNumber*)num;
+- increase;
+- decrease;
 @end