As a father of elementary school students, I would like to allow the students to have fun learning specific words that have been accepted by the teacher for dictation or for an upcoming test - in order to improve the student's grades.
Learning is experiential, and fun - when the student knows the word, slide/drag the card to the right, and if he doesn't know, slide the card to the left.
For the right and left challenges I also introduced know/don't know buttons.
When the cards are finished, I will present a status summary and ask the student to repeat the words he did not know, until he knows how to answer everything.