It should have 4 routes

1. http://localhost:3000/multiply?a=1&b=2
2. http://localhost:3000/add?a=1&b=2
3. http://localhost:3000/divide?a=1&b=2
4. http://localhost:3000/subtract?a=1&b=2

Inputs given at the end after ? are known as query parameters (usually used in GET requests)

The way to get them in an HTTP route is by extracting them from the req argument (req.query.a , req.query.b)

Steps to follow

• Initialize node project

npm init -y

• Install dependencies

npm install express

• Create an empty index.js

touch index.js

• Write the code to create 4 endpoints

const express = require("express");

const app = express();

app.get("/sum", function(req, res) {

});

app.get("/multiply", function(req, res) {
    
});

app.get("/divide", function(req, res) {
    

});

app.get("/subtract", function(req, res) {

});

app.listen(3000);

• Fill in the handler body

const express = require("express");

const app = express();

app.get("/sum", function(req, res) {
    const a = req.query.a;
    const b = req.query.b;

    res.json({
        ans: a + b
    })
});

app.get("/multiply", function(req, res) {
    const a = req.query.a;
    const b = req.query.b;
    res.json({
        ans: a * b
    })
});

app.get("/divide", function(req, res) {
    const a = req.query.a;
    const b = req.query.b;
    res.json({
        ans: a / b
    })

});

app.get("/subtract", function(req, res) {
    const a = req.query.a;
    const b = req.query.b;
    res.json({
        ans: a - b
    })
});

app.listen(3000);

• Test it in the browser

  

<aside> 💡

What do you think is wrong here?

</aside>