This is an all-class mixer activity for reviewing definite articles, indefinites articles and school supplies. Print on cardstock and cut into cards. Students find a partner. Partner A asks his question (Give the singular of unos alumnos); B responds (un alumno). B asks his question (Give the plural of el libro) and A responds (los libros). Students exchange cards and then move on to find new partners. Perfect review activity for right before a test.