index.js

const num1 = Math.ceil(Math.random() * 10);
const num2 = Math.ceil(Math.random() * 10);

const questionE1 = document.getElementById("question");

const inputE1 = document.getElementById("input")

const formE1 = document.getElementById("form");

const scoreE1 = document.getElementById("score")

let score = JSON.parse(localStorage.getItem("score"));

if(!score){
    score = 0;
}

scoreE1.innerText = `score: ${score}`

questionE1.innerText = `What is ${num1} multiply by ${num2}?`;

const correctAns = num1 * num2;

formE1.addEventListener("submit", ()=>{
    const userAns = inputE1.value
    if(userAns == correctAns){
       score++;
       updateLocalStorage()
    }else{
        score--;
        updateLocalStorage()
    }
});

function updateLocalStorage(){
    localStorage.setItem("score", JSON.stringify(score))
}