JSFiddle - React, Tailwind, and code Playground

by Josh Pullen

HTML

<span id="a"></span>
-
<span id="b"></span>
=
<input id="answer" type="number" />

<button id="submit">Check answer</button>

JavaScript

function generate() {
	const a = Math.floor(Math.random() * 10)
  const b = Math.floor(Math.random() * 10)
  
  return { a, b }
}

function check(question, answer) {
	return answer === question.a - question.b
}


///////////////////////////////////////////////////


const question = generate()
document.querySelector("#a").innerText = question.a
document.querySelector("#b").innerText = question.b

document.querySelector("#submit").addEventListener("click", function() {
	const answer = Number(document.querySelector("#answer").value)
  if (check(question, answer)) {
  	alert("Correct!")
  } else {
  	alert("Wrong.")
  }
})