Shortening calculator project code
Write a helper method, e.g.

static Button createButton(Frame f, String label, int x0, int y0, int width, int height) {
    Button b = new Button(label);
    b.setBounds(x0, y0, width, height);
    f.add(b);
    return b;
}


Then your code would simplify to lines like:

createButton(f, "+", 70, 100, 50, 40);


which is a reduction of roughly 2/3.

Of course this does not address the problem that you are trying to do pixel-exact layouts. You should rather be dropping elements on a grid which can be resized freely. (However, it has been a long time since I've used AWT so I can't give an example).