Calc

function calculator() {
    let firstNumElelment;
    let secondNumElement;
    let resultElement;

    return {
        init(selector1, selector2, resultSelector) {
            firstNumElelment = document.querySelector(`${selector1}`);
            secondNumElement = document.querySelector(`${selector2}`);
            resultElement = document.querySelector(`${resultSelector}`);
        },
        add() {
            let firstNum = Number(firstNumElelment.value);
            let secondNum = Number(secondNumElement.value);
            resultElement.value = firstNum + secondNum;
        },
        subtract() {
            let firstNum = Number(firstNumElelment.value);
            let secondNum = Number(secondNumElement.value);
            resultElement.value = firstNum - secondNum;
        }
    };

}