Type your homework into a text (ascii) file, and send it as an email or email attachment. In the "subject" line, put HW3, for example, for homework number 3. This method will sometimes present some challenges. You can handle subscripts like x_i, and superscripts like x^2. If a figure or diagram is needed, you may make an ascii approximation (it need not be pretty, only clear!).
The advantages of this method are that it is quick, cheap, unlikely to get lost, leaves a permanent record, and I can put notes in the file and send it back.
Do not fax assignments; our office is not set up for that and they will likely be lost.