Threw this together for an English Club, very small class (3 students) to be used as filler if we had time. Still if you are looking for something to practice 1-20 with in a small elementary school class this can be useful. If you have a big class I think you'd be better off making actual cards and having the students play in groups. Although this could still be used as a demonstration.
Anyway its concentration.
A student says a number and you click on it revealing a character face. Then the student says another number and you click on it revealing another face. If the two faces match that is one point. In that case you click on the little stars beside the faces and the faces vanish. If they don't match click on the character faces and the cards reappear and its the next student's turn. If you accidentally click on the star making the character vanish then click on the blank space where the character was. That will make the card reappear.