Even those who've never seen a circus show will fred it easy to warm up to personable, eleven-year-old Armando Cristiani (he's billed as nine); who performs with his family on trampoline and horseback, helps with his mother's leopard act, and exercises his own special talent as a solo juggler. And after you've had a look at the Cristianis at their spectacular work you'll even be interested in the genealogical background that follows. For the rest, .you'll travel with Armando on the road (""Sometimes people cry at the end"" of the season) and visit him at his winter home in Florida where, as always, he practices a good four hours a day. (Armando goes to school by mail.) ""Sometimes my mother says I practice too much,"" Armando says. But then, ""It's wonderful having [Lucio Cristiani] for a father because he's a great man. . . . If I'm going to be like my father, I've got to [work hard so as to] be very good."" A lucky boy indeed.