I'm watching a video by freecodebootcamp on youtube called 'Learn JavaScript - Full Course for Beginners' and when they explain 'assignment with returned value' at the 1hour 5minute mark the person has set a value to 'change(num)' then outside of the function sets a value of 10 to it and I just don't seem to understand why he has added the 10 when he gave it a value already form the function.

image of code I am talking about

var changed = 0;

function change(num) {
  return (num + 5) / 3;
}

changed = change(10);

console.log(changed);

(my thought process below)

so you see where he has already given change a value of the outcome of 5/3 which is 1.6

so change = 1.6

then he has changed = changed

which in my mind means changed also = 1.6

but then he adds the (10)

why has he added a value to change if it already had a value of 1.6

what does the 10 do

has it changed the value of 1.6 to 10

I don't understand it and he just skips onto the next thing like it has been explained.

why not just set var changed = 10;