Implement sin function and helper functions such as getSmallAngle and floor.

src/main/java/org/nwapw/abacus/number/NaiveNumber.java

@@ -98,6 +98,11 @@ public class NaiveNumber implements NumberInterface {
         return (int) Math.ceil(value);
     }
 
+    @Override
+    public int floor() {
+        return (int) Math.floor(value);
+    }
+
     @Override
     public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
         if (toClass == this.getClass()) return this;