JSFiddle - React, Tailwind, and code Playground

JavaScript

function calculator(firstNumber){
	this.firstNumber = firstNumber
	
}

calculator.prototype.sum = function(){
	this.result = this.firstNumber;
		for(var i = 0; i < arguments.length; i++){
			this.result = this.result+arguments[i]
		}
		return this.result
	}


function SqrCalc(firstNumber){
	this.firstNumber = firstNumber
} 


SqrCalc.prototype = Object.create(calculator.prototype)

SqrCalc.prototype.sum = function(){
	var result = myCalculator.sum(arguments.length)

	return result * result
}

let myCalculator = new calculator(100);
let myCalculator2 = new SqrCalc(100);


console.log(myCalculator2.sum(1,2,3))