Floating and Double Data Types: assign a float output to a double

Question

When I write this:

float f = 9.87f;
System.out.println(f);

double w = f;
System.out.println(w);

... The output is this:
9.87
9.869999885559082

How does the value change?

Answer 1

The println method is doing that ;)
See
https://stackoverflow.com/questions/17504833/why-converting-from-float-to-double-changes-the-value