let x = 1000; console.log(x.toPrecision(5)); // 1000.0 console.log(x.toPrecision(4)); // 1000 console.log(x.toPrecision(3)); // 1.00e+3 console.log(x.toPrecision(2)); // 1.0e+3 console.log(x.toPrecision(1)); // 1e+3 x = 15.335; console.log(x.toPrecision(6)); // 15.3350 console.log(x.toPrecision(5)); // 15.335 console.log(x.toPrecision(4)); // 15.34 console.log(x.toPrecision(3)); // 15.3 console.log(x.toPrecision(2)); // 15 console.log(x.toPrecision(1)); // 2e+1