text: function addUpTo(n) {
    let total = 0;
    for (let i = 0; i <= n; i++) {
      total += i;
    }
    return total;
  }
  
  let t1 = performance.now();
  addUpTo(1000000000);
  let t2 = performance.now();
  
  console.log(`Time elapsed: ${(t2 - t1) / 1000} seconds`);
  