<button id="calculate">Calculate</button>
<button id="clear">Clear</button>
<pre id="results"></pre>

const results = document.querySelector("#results");

function calculate() {
  for (let i = 1; i < 10; i++) {
    const newResult = `${i} x ${i} = ${i * i}`;
    results.textContent += `${newResult}\n`;
  }
  results.textContent += "\nFinished!\n\n";
}

const calculateBtn = document.querySelector("#calculate");
const clearBtn = document.querySelector("#clear");

calculateBtn.addEventListener("click", calculate);
clearBtn.addEventListener("click", () => (results.textContent = ""));