yes. in general, pre-ejaculate contains less sperm than ejaculatory fluid does. (around here, we generally try to avoid slang terms like "cum" - they confuse everyone's lives.)
that said, how many sperm does it take to get pregnant? oh, that's right. just one. there is no way of knowing exactly how many sperm there are at any given time. it varies.
what you need to know, basically, is that there is a risk from vaginal contact with pre-cum, and that although it may seem negligible, it's not. people have gotten pregnant from it.
also, pre-ejaculate can carry diseases just like any other bodily fluid! so condoms, condoms, condoms. :-D
Boys and girls in America have such a sad time together; sophistication demands that they submit to sex immediately without proper preliminary talk. Not courting talk - real straight talk about souls - for life is holy and every moment is precious. I heard the Denver and Rio Grande locamotive howling off in the mountains. I wanted to pursue my star further. -Kerouac