Project on Earning a Living

My learners are really excited about the new project Earning to Live.

They'll be running business in and outside school for a month.

the objectives are:

understanding the economic structure
calculating profit and loss
writing business plans
and pursuasive speeches

I've started the project with discussion of primary, secondary and tertiary activities. However, i feel i should have first asked them to identify a business they would have liked to do 
and then moved on to the technical terms for it.