fix(calculator.ts): revert the previous "useless" fix

Author: gfmio

src/Calculator.ts

@@ -73,8 +73,6 @@ export default class Calculator {
   }
 
   public inverse() {
-    this.current = div(1, this.current);
-    this.current = div(1, this.current);
     this.current = div(1, this.current);
     return this;
   }