A teaching system including a database including multiple question/answer sets, wherein substantially each question/answer set includes a question and at least one correct answer, and wherein at least two sets are adapted to test substantially a same data item; and a presentation module adapted to present to a user a second question/answer set relating to a first data item immediately following or subsequent to the user correctly responding to a first question/answer set relating to the first data item, and said presentation module further adapted to stop presenting question/answer sets related to the first data item once the user has responded correctly to two question/answer sets relating to the first data item without incorrectly responding to a question/answer set related to the first data item.