After giving students the definition of a logarithm,

divide the class into pairs or groups of three. Each group is given two envelopes containing several index cards (Four sets of sample cards appear below). Each group is given about three minutes to make correct mathematical statements using the cards in the envelopes. Not all cards in the envelope are used in the equation. At a signal, a spokesperson for each group reads the equations and I write them on the chalkboard, grouping similar equations together.

The students then try to formulate a general statement that summarizes the pattern found in the groups of similar questions.

We write these conjectures above each group:

     

Here is a set of sample cards: