It depends on what you want. We gave our students voluntary additional exorcice, and we gave them 1 point for a correct answer and .5 in the second guess. The i

It depends on what you want. We gave our students voluntary additional exorcice, and we gave them 1 point for a correct answer and .5 in the second guess. The idea was to encourage them to learn from their first mistake (and perhaps some clue, like "remember the parenthesis" or "(a/b)/(c/d) is not (ac)/(bd)")