diff --git a/index.html b/index.html
index a1f0995..50d7e32 100644
--- a/index.html
+++ b/index.html
@@ -14,7 +14,7 @@
     <div id="mocha"></div>
     <script src="node_modules/mocha/mocha.js"></script>
     <script src="node_modules/expect/umd/expect.min.js"></script>
-    <script src="node_modules/sinon/pkg/sinon.js"></script>
+https://learn.co/tracks/accelerated-prep/week-2/functions-and-scope/javascript-arithmetic-lab#    <script src="node_modules/sinon/pkg/sinon.js"></script>
     <script>mocha.setup('bdd');</script>
     <script src="index.js"></script>
     <script src="test/index-test.js"></script>
diff --git a/index.js b/index.js
index e69de29..d0127ac 100644
--- a/index.js
+++ b/index.js
@@ -0,0 +1,34 @@
+function add(a, b) {
+  return a + b
+}
+
+function subtract(a, b) {
+  return a - b
+}
+
+function multiply(a, b) {
+  return a * b
+}
+
+function divide(a, b) {
+  return a / b
+}
+
+function inc(n) {
+  return n += 1
+}
+
+function dec(n) {
+  return n -= 1
+}
+
+function makeInt(n) {
+  return parseInt(n, 10)
+}
+
+function preserveDecimal(n) {
+  return parseFloat(n)
+}
+
+
+