Farmerama is a free MMORPG - although a young child can play on their own unaware of other online players. The idea is simple - you are a farmer. The execution though, as any farmer knows, is a lot of; planning, critical thinking, organising, calculating, managing funds, and decision making.
You have crops and livestock, which you have to care for and harvest. Eventually you sell your produce at a city market. This is real life selling (game money) that other players are buying from you. What is amazing to me, is that the market behaves dynamically - that is, prices fluctuate and are determined by supply and demand, just like a real market.
Profits are essential to maintain your farm. So you have to carefully manage your money, sow the most profitable crops, and sell often. The older the child, the more involved they can become with all these aspects.
For now, tending her farm, including choosing which crops to sow and feeding her animals, is her focus. I guide her along at the market.
A really powerful life skills and maths game that because it isn't created as an educational game doesn't feel like one!