sandbox-js/calculator.js

const prompt = require("prompt-sync")({sigint: true});

function add(a, b) {
	let e = a + b;
	return e;
}

let c = prompt("Num 1: ");
let d = prompt("Num2: ");
let op = prompt("What operation? ");

if (op == "+") {
	console.log(Number(c) + Number(d));
}

if (op == "-") {
	console.log(Number(c) - Number(d));
}