There is no specific number of designated areas, depending on the structure of your own house. Generally 10- 15 is enough, and winter and summer are too big for children. Just leave some room for exercise. It's not necessary to be so big.

By the way, in the active world of children room design, the ground should be wear-resistant and durable. Usually, some of the most practical and economical choices are to paint wooden floors or other more elastic materials, such as cork, oak, plastic and tarpaulin. However, all these flooring materials can't prevent accidents like carpets, such as knee injuries or falls. If you want to have both, you should lay a carpet on a solid, wear-resistant and elastic floor.