diff --git a/README.md b/README.md
index 1e741a3..c842a65 100644
--- a/README.md
+++ b/README.md
@@ -32,9 +32,9 @@ That's actually a good question. I guess that discovery does not happen with a s
 
 # How to run?
 
-from console, install jest
+from console, install with npm:
 ```
-npm install --save-dev jest
+npm install
 ```
 
 then you can just run the tests
@@ -45,4 +45,4 @@ npm test
 if you want to benchmark use
 ```
 npm run bench
-```
\ No newline at end of file
+```
diff --git a/javascript/The73Calculator.js b/javascript/The73Calculator.js
index 2fa89c6..893dd29 100644
--- a/javascript/The73Calculator.js
+++ b/javascript/The73Calculator.js
@@ -77,6 +77,12 @@ module.exports = class The73Calculator {
         return n;
     }
 
-    static noop(n) {}
+    static octal(n) {
+        let numberAsOctal = (n + 4).toString(8)
+        numberAsOctal = parseInt(numberAsOctal) % 10
+
+        return numberAsOctal;
+    }
 
+    static noop(n) {}
 };
\ No newline at end of file
diff --git a/javascript/The73Calculator.test.js b/javascript/The73Calculator.test.js
index 58ba8ce..3b62099 100644
--- a/javascript/The73Calculator.test.js
+++ b/javascript/The73Calculator.test.js
@@ -53,14 +53,12 @@ describe("The73Calculator", () => {
     test(The73Calculator.usingPolynom.name, () => {
         expectBehavior(The73Calculator.usingPolynom);
     });
-
-
-
+    test(The73Calculator.octal.name, () => {
+        expectBehavior(The73Calculator.octal);
+    });
 
     function expectBehavior(f) {
         expect(f(3)).toBe(7);
         expect(f(7)).toBe(3);
     }
-
-
 });
\ No newline at end of file