diff --git a/index.js b/index.js
index 3bb4d07..78c43e2 100644
--- a/index.js
+++ b/index.js
@@ -4,7 +4,67 @@
  * Depending on the operation, either add up all of the numbers or subtract all of the numbers, from left to right.
  * @returns {number} The result of either adding all numbers or subtracting all numbers, depending on the arguments added to the command line.
  */
-function calculator() {}
+function calculator() {
+    let numbers = []
+    if (!process.argv[2]) {
+        return "No operation provided..."
+    } else if (!process.argv[3]) {
+        return "No numbers provided..."
+    } else if (process.argv[2] !== 'plus' && process.argv[2] !== 'minus') {
+        return `Invalid operation: ${process.argv[2]}`
+    } else {
+        for (let i = 3; i < process.argv.length; i++) {
+            numbers.push(+process.argv[i])
+        }
+        if (process.argv[2] === 'plus') {
+            numbers = numbers.reduce((current, next) => current + next)
+        } else if (process.argv[2] === 'minus') {
+            numbers = numbers.reduce((current, next) => current - next)
+        }
+        return numbers
+    }
+}
+/*========================================OTHERWAYS OF SOLVING==========================================*/
+
+    // if (!process.argv[2]) {
+    //     return "No operation provided..."
+    // } else if (!process.argv[3]) {
+    //     return "No numbers provided..."
+    // } else if (process.argv[2] !== 'plus' && process.argv[2] !== 'minus') { 
+    //     return `Invalid operation: ${process.argv[2]}` 
+    // } else if (process.argv[2] === 'plus') {
+    //     for (let i = 3; i < process.argv.length; i++) {  //We start at 3 so that we skip the file paths and the operation
+    //         //we need to turn the string
+    //         total += ~~process.argv[i]
+    //     }
+    //     return total
+    // } else if (process.argv[2] === 'minus') {
+    //     total = parseInt(process.argv[3])
+    //     for (let i = 4; i < process.argv.length; i++) {  //We start at 4 since we assigned total the value of the third index of process.argv
+    //         total -= Number(process.argv[i])
+    //     }
+    //     return total
+    // }
+/*------------------------------------------------------------------------------------------------------*/
+// let total = 0
+// if( process.argv.length === 2 ){
+//     return "No operation provided..."
+// }else if(process.argv[2] !== 'plus' && process.argv[2]!=='minus'){
+//     return 'Invalid operation: modulo'
+// }else if(process.argv.length === 3 || process.argv[3]*1 ===NaN){
+//     return 'No numbers provided...'
+// }
+// for (let i = 3; i < process.argv.length; i++) {
+//     if (process.argv[2] === 'plus') {
+//         total += +process.argv[i]
+//     } else if (process.argv[2] === 'minus') {
+//         if (i === 3) {
+//             total = +process.argv[i]
+//         } else total -= +process.argv[i]
+//     }
+// }
+// return total
 
 // Don't change anything below this line.
 module.exports = calculator;
+
diff --git a/package-lock.json b/package-lock.json
index 99b1c39..ce6f0ea 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -5,6 +5,7 @@
   "requires": true,
   "packages": {
     "": {
+      "name": "8-0-javascript-on-your-machine-lab",
       "version": "1.0.0",
       "license": "ISC",
       "devDependencies": {