20 cubes
64
Infinitely many.
A rectangular prism that is 4 cubes by 2 cubes is made up of 8 cubes.
24 of them
18
You could try 14!
20 cubes
64
You can make four.
its 3
Infinitely many.
-4
A rectangular prism that is 4 cubes by 2 cubes is made up of 8 cubes.
about 10
24 of them
25