README.md in factbase-0.0.57 vs README.md in factbase-0.0.58

@@ -95,9 +95,15 @@
 * `(plus v1 v2)` is a sum of `∑v1` and `∑v2`
 * `(minus v1 v2)` is a deducation of `∑v2` from `∑v1`
 * `(times v1 v2)` is a multiplication of `∏v1` and `∏v2`
 * `(div v1 v2)` is a division of `∏v1` by `∏v2`
 
+Types may be converted:
+
+* `(to_int v)` is an integer of `v`
+* `(to_str v)` is a string of `v`
+* `(to_float v)` is a float of `v`
+
 One term is for meta-programming:
 
 * `(defn f "self.to_s")` defines a new term using Ruby syntax and returns `true`
 * `(undef f)` undefines a term (nothing happens if it's not defined yet),
 returns `true`