It depends on where you are when trying to use it. You can build a calculated field in a table in Access 2010 (although it isn't probably the best to use except if you have a web app and can't do aggregates because of that). But now that I go back and look at the screenshot again, you would have had to expand the ProWideFoods.accdb area which would have given you tables/queries, etc. The TEST thing that was at the top is the query you were in.
So anyway, if you had typed in the expression you wanted in the query itself, intellisense (new in queries in 2010) would have assisted. It is pretty cool to have that.