Why do the numbers themselves add more than given?

Question

JavaScript

let x = 12;
let y = 14;

x += 2.4;
y += 2.8;

here is a simple formula that the bot executes on a specific command and everything is fine, but every time the numbers x and y go beyond the number 20, for example:

y += 2.8 // enter the command 1 time y = 16.8
y += 2.8 // 2 once I enter the command y = 19.6
y += 2.8 // 3 times I enter the command y = 22.400000000000002

why do the numbers walk like that if I set the exact parameters of the formula?

Answer 1

Because .