Maths Q&A game in JavaScript

This used to be university work now I put it our here for review purposes.

• Could this be constructed better?

• Is there any easier path, performance-wise?

• Could this be optimised?

• Which features and functionalities could/should be added to this game?

`

Math.floor

Math.floor: The Maths Game


// Universty work
// @author Darik
// Math.floor

var score = 0;
var times = 0;

function questions(e) {
var x = Math.floor(Math.random() * 11);
var y = Math.floor(Math.random() * 11);
var z = 0;
var sign = '';

if (e == 1) {
sign = '+'
z = x + y;
interact(x, sign, y, z)
} else if (e == 2) {
sign = '-'
z = x - y;
interact(x, sign, y, z)
} else if (e == 3) {
sign = '/'
z = x / y;
interact(x, sign, y, z)
} else {
sign = '*'
z = x * y;
interact(x, sign, y, z)
}

}

function interact(x, sign, y, z) {
times++;
var userAnswer = prompt("What is " + x + " " + sign + ' ' + y + "?");
if (z == userAnswer) {
document.write("
" + x + " " + sign + ' ' + y + " = " + userAnswer + " is correct ");
score = score + 1;
} else {
document.write("
" + x + " " + sign + ' ' + y + " = " + userAnswer + " is INCORRECT. The correct answer is " + z + "");
}
}

function _score() {
if (times == score) {
document.write('
A perfect score ');
document.body.style.backgroundColor = "#FF99CC";
} else {
document.body.style.backgroundColor = "#CCFFFF";
}
document.write('
You have answerd ' + score + ' questions out

You ask some unreasonable division questions.

That is answerable by the special string Infinity, but not infinity.

The expected answer is NaN, but responding with NaN will not work.


10 / 3 = 3.33333333 is INCORRECT. The correct answer is 3.3333333333333335

StackExchange Code Review Q#84413, answer score: 6