What is meaning of this statement, in js?

Question

document.write(x-.y);

Answer 1

x-.y
lets x is a number 5,y must be a decimal less than 1 like...0.5
so
document.write(1-0.5); or..
document.write(1-.5);
.y is an abbreviation for 0.y
like .7 is 0.7
.9 is 0.9 e.t.c

Answer 2

document. write is virtually same thing as print out or write this to the page