Children and African dance are a magical combination. African dance is like problem solving for the body: the task is to complete certain motions to prescribed beats in a given amount of time. The interest lies in the way each body, with its own rhythms and weight and range of motion, comes up with a different solution. Older, seasoned dancers often solve these polyrhythmic puzzles as elegantly as mathematicians do equations: we marvel at their economy and integrity. But it's great fun to watch young dancers feel their way to their own solutions, to watch them negotiate their rapidly changing bodies. Watching Alyo Children's Dance Theatre perform these essentially social and ceremonial dances, the province of all ages, you seem to see the continuity of life, the village to which we all belong. Since more than 100 children age 4 to 17 participate in Alyo, you know the energy is going to be strong; and the children's discipline and professionalism channel that power. They'll be performing company favorites like the South African Boot Dance as well as new works like Dakar, which combines Senegal's official dance with a cultural tradition resembling Halloween, at "Saba: Seven," the troupe's seventh annual concert. Saturday at 7 and Sunday at 3 in the Katherine Dunham Theatre of Kennedy-King College, 6800 S. Wentworth; $8 in advance, $10 at the door. Call 907-2193 for tickets and information.