# Amena # Let's make a Basic Calculator with JS in 4 minutes

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>
<script src="calc.js"></script>
<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 != "*") {
} 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 != "*") {
} 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);
}
}
``````

## 9. Else If statement for division➗

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

if (op != "+" && op != "-" && op != "/" && op != "*") {
} 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 != "*") {
} 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! 👋🙋‍♀️ 