Please help me to understand multiple assignment operators

Question

I can't figure out how it works! can someone help me why I get an output of 11 for variable c in the code below?

var a = 10;
var b = 3;
var c = 2;
c += a -= b -= c;
document.write(a); // output: 9
document.write(b); // output: 1
document.write(c); // output: 11

Answer 1

Read it from the right to the left:

b -= c => b -= 2 => b = 1
a -= b => a -= 1 => a = 9
c += a => c += 9 => c = 11

Answer 2

Thanks! It's now make sense to me

Answer 3

You're welcome 🙂