How do I explain my incomplete university degree on a resume/cover letter?

I'm trying to write a cover letter for a resume and want to explain the skills and qualities that I have gained from working towards my degree, though I haven't finished it (I'm only four elective courses away from completion). I have been working steadily towards my degree for the last few years and have all of my core credits, but I took time off to be closer to my son. I want to finish my degree online while I work since I no longer have any upper year courses to take. However, I don't want my potential employer to think that I'm a dropout because I do plan on finishing. I have an obligation to take care of my child first and foremost, which means pushing my degree back further on the timeline.

Thank you guys in advance for any information or advice you can give.