Good afternoon M�rcia! You�re right when you say it is not the Pesent Continuous Tense, but I believe the contributor didn�t mean to say that, either, because in his description we can read that he wants to help pupils "to form present continuous verbs (notice, not tenses) by adding -ing suffix". So, what he wants his students  to learn is the -ing form of the verbs, or the Present Participle, as you have said, and the exercise he chose proves that.