The Café Assistant will do much of the work for you. Simply type in rule names and numbers, press tab, and use a slash or two instead of a sentence. The Café will fill in from there.
For all rules of inference, you may type the justification, then type '/' or '//', TAB, and an approriate sentence will appear.
This page allows you to enter any problems of your choosing. Experiment by entering 'P' for premise and then the sentence '(A&C)>(B&D)'. Try to derive '~(B&D)>~(A&C)'. The sentences are long, so you'll be glad to have the '/' shortcut.
Reward Link: To use this page and the Café Assistant you'll first need the password. To find out where to get this password, you'll need to complete the SD problem set.