This is a very simple activity that has the potential to run on and on ! The children have loved it every time I have done it with them and ask when they are going to be doing it again….can't be bad !
The work fits nicely into the 'Real Maths' part of the NNS, although it was actually conceived a few years before the introduction of the NNS, and is centred around running a bike shop.
I chose a bike shop as I happened to be in contact with one at the time and they let me have 40 copies of their catalogue. The same idea could be adapted to any catalogue, especially the famous 'Argos' catalogue which caters for a wide variety of interests. The fact that it was a bike shop didn't matter to the children who found the whole idea very exciting.
How Does It Work ?
The idea is very flexible and can be adapted in any way you like, the great thing is that the children get to do lots of real maths !

Idea 1-- Give the children a fixed amount of money and instruct them that they have to buy stocks for their shop, these must include a variety of different items. They should not go over the fixed sum.
Idea 2-- The children could now decide what they will sell each item for and work out how much profit they have made. The profit can then be put into buying more stock, and so the process rolls on
Idea 3-- Again the children are given a fixed amount of money but this time they have to spend a certain percentage of the money of various categories. Once they have bought the stock they must add on 20% profit and calculate how much profit they will actually make on the goods they have bought. Once again the profit can be ploughed back into buying more stock.

Extending the activity--

• I let the children lay the figures out how they wished, but you may wish to give them a proper accounts sheet.
  
• You could tell the children that a certain percentage of the profits needs to go towards salaries, heating, rent etc.
  
• The calculations and recording could be done on a spreadsheet.
  
• What really works well is when you run this as a maths / DT project and actually give the children £5.00 (for each group of around 4) to start their business, buy materials, make and item and sell at a profit. They have to repay the loan and keep and profit they make. The last time I did this the children were selling each other shares in their companies with no prompting from me !