diff --git a/src/core/config/Categories.js b/src/core/config/Categories.js
index f04b5fd9..7faa75f2 100755
--- a/src/core/config/Categories.js
+++ b/src/core/config/Categories.js
@@ -159,6 +159,7 @@ const Categories = [
     {
         name: "Utils",
         ops: [
+            "Arithmetic",
             "Diff",
             "Remove whitespace",
             "Remove null bytes",
diff --git a/src/core/config/OperationConfig.js b/src/core/config/OperationConfig.js
index 81444880..65d1d065 100755
--- a/src/core/config/OperationConfig.js
+++ b/src/core/config/OperationConfig.js
@@ -660,8 +660,8 @@ const OperationConfig = {
     "Arithmetic": {
         module: "Default",
         description: "Conducts mathamatical operations on a list of numbers",
-        inputType: "string"
-        outputType: "string"
+        inputType: "string",
+        outputType: "string",
         args: [
             {
                 name: "Delimiter",
@@ -669,7 +669,7 @@ const OperationConfig = {
                 value: Arithmetic.DELIM_OPTIONS
             },
             {
-                name: "Operation"
+                name: "Operation",
                 type: "option",
                 value: Arithmetic.OPERATIONS
             }
diff --git a/src/core/config/modules/Default.js b/src/core/config/modules/Default.js
index 682db223..5f049ac7 100644
--- a/src/core/config/modules/Default.js
+++ b/src/core/config/modules/Default.js
@@ -1,4 +1,5 @@
 import FlowControl from "../../FlowControl.js";
+import Arithmetic from "../../operations/Arithmetic.js";
 import Base from "../../operations/Base.js";
 import Base58 from "../../operations/Base58.js";
 import Base64 from "../../operations/Base64.js";
@@ -155,6 +156,7 @@ OpModules.Default = {
     "Conditional Jump":     FlowControl.runCondJump,
     "Return":               FlowControl.runReturn,
     "Comment":              FlowControl.runComment,
+    "Arithmetic":           Arithmetic.runOp,
 
 
     /*
diff --git a/src/core/operations/Arithmetic.js b/src/core/operations/Arithmetic.js
index 8a840a29..ef6643e4 100644
--- a/src/core/operations/Arithmetic.js
+++ b/src/core/operations/Arithmetic.js
@@ -23,20 +23,6 @@ const Arithmetic = {
      */
     OPERATIONS: ["Sum", "Sub", "Multiply", "Divide", "Mean", "Median", "Mode"],
 
-    /**
-     * A mapping of operation names to their function.
-     * @constant
-     */
-     opMap: {
-         "Sub":         _sub,
-         "Sum":         _sum,
-         "Multiply":    _multiply,
-         "Divide":      _divide,
-         "Mean":        _mean,
-         "Median":      _median,
-         "Mode":        _mode,
-     },
-
     /**
      *
      *
@@ -48,13 +34,12 @@ const Arithmetic = {
         const delim = Utils.charRep[args[0] || "Space"];
         let splitNumbers = input.split(delim),
             numbers = [],
-            num,
-            retVal;
-        for (i = 0; i < splitNumbers.length; i++) {
-            if splitNumbers[i].indexOf(".") {
+            num;
+        for (let i = 0; i < splitNumbers.length; i++) {
+            if (splitNumbers[i].indexOf(".") >= 0) {
                 num = parseFloat(splitNumbers[i].trim());
             } else {
-                num = parseInt(splitNumbers[i].trim());
+                num = parseInt(splitNumbers[i].trim(), 10);
             }
             if (num !== "NaN") {
                 numbers.append(num);
@@ -68,19 +53,33 @@ const Arithmetic = {
     },
 
 
+    /**
+     * Adds an array of numbers and returns the value.
+     *
+     * @private
+     * @param {number[]} data
+     * @returns {number}
+     */
     _sum: function(data) {
         let total = 0;
-        for (i = 0; i < data.length; i++) {
+        for (let i = 0; i < data.length; i++) {
             total += data[i];
         }
         return total;
     },
 
+    /**
+     * Subtracts an array of numbers and returns the value.
+     *
+     * @private
+     * @param {number[]} data
+     * @returns {number}
+     */
     _sub: function(data) {
         let total = 0;
         if (data.length > 1) {
             total = data[0];
-            for (i = 1; i < data.length; i++) {
+            for (let i = 1; i < data.length; i++) {
                 total -= data[i];
             }
         } else {
@@ -89,11 +88,18 @@ const Arithmetic = {
         return total;
     },
 
+    /**
+     * Multiplies an array of numbers and returns the value.
+     *
+     * @private
+     * @param {number[]} data
+     * @returns {number}
+     */
     _multiply: function(data) {
         let total = 0;
         if (data.length > 1) {
             total = data[0];
-            for (i = 1; i < data.length; i++) {
+            for (let i = 1; i < data.length; i++) {
                 total *= data[i];
             }
         } else {
@@ -102,12 +108,19 @@ const Arithmetic = {
         return total;
     },
 
+    /**
+     * Divides an array of numbers and returns the value.
+     *
+     * @private
+     * @param {number[]} data
+     * @returns {number}
+     */
     _divide: function(data) {
         let total = 0;
         if (data.length > 1) {
             total = data[0];
-            for (i = 1; i < data.length; i++) {
-                total /= data[i]
+            for (let i = 1; i < data.length; i++) {
+                total /= data[i];
             }
         } else {
             total = null;
@@ -115,6 +128,13 @@ const Arithmetic = {
         return total;
     },
 
+    /**
+     * Finds the mean of a number array and returns the value.
+     *
+     * @private
+     * @param {number[]} data
+     * @returns {number}
+     */
     _mean: function(data) {
         let total = 0;
         if (data.length > 1) {
@@ -125,6 +145,18 @@ const Arithmetic = {
         return total;
     },
 
+    /**
+     * A mapping of operation names to their function.
+     * @constant
+     */
+    opMap: {
+        "Sub":         Arithmetic._sum,
+        "Sum":         Arithmetic._sub,
+        "Multiply":    Arithmetic._multiply,
+        "Divide":      Arithmetic._divide,
+        "Mean":        Arithmetic._mean,
+    },
+
 };
 
 export default Arithmetic;