## Table of contents

**Hello Legends👋**

So, in this article I am gonna show you guys that how to make a basic calculator with JavaScript in 2 minutes only!

**So without any further do let's get started...**

## 1. Open VS code💡

Step 1. In VS code install your live server Extension!!

Step 2. After installing Live server extension click on `Go live`

:

You can clearly see where is `Go live`

👆

Now let's start to code:👩💻

## 2. Connect with HTML: (Create index.html)

```
<html>
<head>
<script src="calc.js"></script>
</head>
<body></body>
</html>
```

## 3. Start code (Create Variable) 💡

Create a new file like I have created `calc.js`

```
let op;
```

## 4. Take input✨

for taking input we are having a function called `prompt()`

the `prompt()`

function always output a `string`

...

```
let op = prompt("Enter operation (+, -, *, /)");
```

**Make sure guys that you must click** `ctrl + s`

after every change!! **Go to your browser and refresh it.**

You'll see:

Yeeeeeeeeeepeeee!!

## 5. Take 1st and 2nd number as input🧶

```
let op = prompt("Enter operation (+, -, *, /)");
let firstNumber = prompt("Enter first number");
let secondNumber = prompt("Enter second number");
```

**Here we have made 2 variables** `firstNumber`

and `secondNumber`

and we have taken `input`

by `prompt`

function!!

**Now see the magic: **

1st put an operation: (I have put + operator) 👇

2nd :Enter First number:👇 (I have putted 2)

3rd :Enter Second number:👇 (I have putted 3)

**So, we are not getting anything right??**

Let's make it to calculate the numbers!!

## 6. If statement for addition➕

```
let op = prompt("Enter operation (+, -, *, /)");
let firstNumber = prompt("Enter first number");
let secondNumber = prompt("Enter second number");
if (op == "+") {
document.write(+firstNumber + +secondNumber);
}
```

### 6.1 String to Number

So guys let's assume if I write here:`document.write(firstNumber + secondNumber)`

then the output would come jointed like

if I enter the operation **+** and first number **2** and second number **3** then it would come **23** because we had not converted into a number it is still a string only!

So If I convert it into a number it would come to the correct total like `2+3 = 5`

to convert a string to a number I have used `+`

sign LIKE THIS:👇

```
if (op == "+") {
document.write(+firstNumber + +secondNumber);
}
```

Isn't it interesting...

**Here we have created the addition method!🎉🎈🥳🎊**

## 7. Else If statement for subtraction➖

```
let op = prompt("Enter operation (+, -, *, /)");
if (op != "+" && op != "-" && op != "/" && op != "*") {
document.write("Invalid operation (please try again!)");
} else {
let firstNumber = prompt("Enter first number");
let secondNumber = prompt("Enter second number");
if (op == "+") {
document.write(+firstNumber + +secondNumber);
} else if (op == "-") {
document.write(+firstNumber - +secondNumber);
}
}
```

**Here we have created the subtraction method too🤩**

## 8. Else If statement for multiplication✖

```
let op = prompt("Enter operation (+, -, *, /)");
if (op != "+" && op != "-" && op != "/" && op != "*") {
document.write("Invalid operation (please try again!)");
} else {
let firstNumber = prompt("Enter first number");
let secondNumber = prompt("Enter second number");
if (op == "+") {
document.write(+firstNumber + +secondNumber);
} else if (op == "-") {
document.write(+firstNumber - +secondNumber);
} else if (op == "*") {
document.write(+firstNumber * +secondNumber);
} else if (op == "/") {
document.write(+firstNumber / +secondNumber);
}
}
```

**A multiplication feature also added😊**

## 9. Else If statement for division➗

```
let op = prompt("Enter operation (+, -, *, /)");
if (op != "+" && op != "-" && op != "/" && op != "*") {
document.write("Invalid operation (please try again!)");
} else {
let firstNumber = prompt("Enter first number");
let secondNumber = prompt("Enter second number");
if (op == "+") {
document.write(+firstNumber + +secondNumber);
} else if (op == "-") {
document.write(+firstNumber - +secondNumber);
} else if (op == "*") {
document.write(+firstNumber * +secondNumber);
} else if (op == "/") {
document.write(+firstNumber / +secondNumber);
}
}
```

**Here we have created all the basic things like** `+, -, *, /`

😀

You can check it out after reading it!!

Now, the calculator is ready but but but... if the user enters something else instead of `+, -, *, /`

so what do we do?? We are also having the right solution of it!!!!!!🎉🎉

**Let's do that!!👇**

## 10. Solution💎

```
let op = prompt('Enter operation (+, -, *, /)')
if (op != "+" && op != "-" && op != "/" && op != "*") {
document.write("Invalid operation (please try again!)")
} else {
let firstNumber = prompt('Enter first number')
let secondNumber = prompt('Enter second number')
}
```

**This is because if the user puts something else so it would come** `invalid operation(please try again!!`

Like if I put any letter or number or any other sign it would come: 👇

And if I put the correct operation like `(+, -, *, /)`

It works!!🎉

## 11. Final Code (Basic Calculator done )🔑

So guys, hope you enjoyed this 3 minutes basic calculator-making process!!

For now goodbye! 👋🙋♀️