Recently, we have been trying to implement more math into the free-flowing curriculum of the Purple Room. Teacher Kate had the idea to use her Tea Party station as a prime learning opportunity with the snack store. 
Children were given 5 Unifix cubes and the choice of several snack items for purchase at prices of 1-3 cubes. The items were priced based on estimated value of the item to the children. For instance, the tea was 1 unit while Goldfish (a very popular snack time request) cost 3 cubes. Children had to budget to give themselves the best mix of food and drink. They enjoyed the tea party as an overarching concept and got the added benefit of using their understanding of numbers to their advantage.
In the afternoon, the snack store continued, but with a change in format. Rather than the value of the individual food or drink items, the prices were based on quantity. One "unit" of banana, raisins, Goldfish, or tea cost 1 cube. The unit:cube ratio became a better value as the price went up (e.g. 1 cube= a slice of banana, 2 cubes= a hunk of banana, 3 cube= half a banana). Children had to think carefully about which items they wanted more of and how they could get the best value for their money (e.g. 2 Goldfish at 1 cube per Goldfish or a scoop of Goldfish for 2 cubes). After the children spent their first 5 cubes, I gave them another set, asking them to budget ahead and use all 5 cubes in one purchase.
In the afternoon, the snack store continued, but with a change in format. Rather than the value of the individual food or drink items, the prices were based on quantity. One "unit" of banana, raisins, Goldfish, or tea cost 1 cube. The unit:cube ratio became a better value as the price went up (e.g. 1 cube= a slice of banana, 2 cubes= a hunk of banana, 3 cube= half a banana). Children had to think carefully about which items they wanted more of and how they could get the best value for their money (e.g. 2 Goldfish at 1 cube per Goldfish or a scoop of Goldfish for 2 cubes). After the children spent their first 5 cubes, I gave them another set, asking them to budget ahead and use all 5 cubes in one purchase.
Through the different store formats, they learned different meanings behind value and thought about their needs and desires in a different context. They used their social skills through negotiating power (e.g. "Can this chunk be 1?", referring to raisins priced at 1 cube per raisin). And, they used their math skills in order to plan ahead for a more well-rounded snack experience.
They were empowered by their own decision making abilities, and they were able to gain real-world experience in the value of understanding numerical concepts.
