24. There are 10 circles on a sphere, these 10 circles can divide the sphere into at least $\qquad$ regions, and at most $\qquad$ regions.
24. 11, 92.

When these 10 circles do not intersect each other, the number of regions on the sphere is the least, which is 11.

When these 10 circles intersect each other pairwise and no three circles intersect at the same point, the number of regions on the sphere is the most. Each circle is divided into 18 segments, and if we unfold the sphere and consider it as a planar graph, the number of vertices (intersection points) is $\frac{18 \times 10}{2}$, and the number of edges (circular arcs) is $18 \times 10$. By Euler's formula, the number of faces is $18 \times 10 + 2 - \frac{18 \times 10}{2} = 92$.