JSFiddle - React, Tailwind, and code Playground

HTML

What is <mark>10 * 10 + 6 = </mark><input id="userInput"><br>
<button onclick="calcAnswer('106')">Submit</button><br>

<p id="response"></p>

CSS

.wrongAnswer{
  text-decoration: line-through;
  color: red;
}
.correctAnswer{
  color: green;
}

JavaScript

function calcAnswer(answer){
    let userInput = document.querySelector('#userInput');
    let userAnswer = Number(userInput.value);
    let response = document.querySelector('#response');
    if(answer == userAnswer){
        response.innerHTML = `<span class="correctAnswer">${answer}</span> was the correct Answer.`;
    }else{
        response.innerHTML = `<span class="wrongAnswer">${userAnswer}</span> was not correct.
        <span class="correctAnswer">${answer}</span> was the correct answer. `;
    }
}