2.7, 3.7, 4.10

2.7
1.
255, 255, 255
0,0,0
0,0,255
128,128,128.
2.
Frames are used for housing the elements of the GUI, panels show colors, text or images, and layout managers determine how everything in multiple panels and frames are laid out.
3.
A border layout arranges panels in 5 places, top, left, right, bottom, and center.
4.
pane.setLayout( new GridLayout(5, 5));
pane.add(panel1)
pane.add(panel2)
pane.add(panel3)
…
pane.add(panel25)
3.7
1.
drawRect (int 45, int 20, int 100, int [...]

12.1

1.
Recursive definitions are not circular because finding sum(n) is finding the sum of n + whatever comes before n, cycling down to 1.
2.
a recursive method must have a stopping state and a recursive step.
3.
4.
Using recursion allows a user to find large sums or the sum of a large series of numbers.
5.
2 x 5
2 x 4
2 [...]