createCanvas(200, 200);

  background(200);

  number1 = createInput('enter a number');

  number1.position(20, 20);

  symbolAdd = createP('+');

  symbolAdd.position(20, 25);

  number2 = createInput('enter a number');

  number2.position(20, 62);

  symbolEqual = createP('=');

  symbolEqual.position(20, 70);

  answer = createP('?');

  answer.position(35, 70);

  button = createButton('Calculate');

  button.position(120, 170);

  button.mousePressed(giveAnswer);

​

}

​

function giveAnswer() {

  let ans = add(number1.value(), number2.value());

  answer.html(ans);

}

​

function add(n1, n2) {

  n1 = int(n1);

  n2 = int(n2);

  return n1 + n2;

}