Javascript rounding issue difference [duplicate]

This is going to be my first question. Just started Automation with javascript and stuck on rounding issue. In this screen shot not sure value of A is different than B even the formula is same?

My Ideal expectation of value a is 0.1985 and b is 0.3035

let a = 0.198450;let b = 0.303450;
a = Math.round(a * 10000) / 10000;
b = Math.round(b * 10000) / 10000;
console.log("a Value is :  "+a);
console.log("b Value is : "+b);