Essentially what we did was, together ("whole class"), work through the questions on how many slaves work for you on the site Larry recommended, negotiating our collective answer in each case, rather than doing it individually or in pairs. Doing so, and having to agree on an answer for the group as a whole, gave rise to a lot of discussion and language use (which, in a language class, was after all the point of the exercise).
In comparison, we actually made very little use of technology (we were using an interactive whiteboard, which strictly speaking wasn't necessary).
In the image shown, my own result, not that we agreed on (which was embarrassingly high!).