JavaScript arithmetic subtraction giving extra unwanted decimal digits

Question

var a = 8.4286;
var b = 2;
console.log(a-b)

Actual Output: 6.428599999999999

Expected Output: 6.4286

What is the reason behind this and how to get around it?

Answer 1

You can use .toFixed:

var a = 8.4286;
var b = 2;
let sub = a-b;
sub = sub.toFixed(4);
console.log(sub);