: "Un trois demi intègre l'X entre la première et la deuxième année car l'intègrale de x de 1 à 2 fait 3/2." "A 'three half' integrates/enrolls in X (Polytechnique) between the 1st and 2nd year because the integral of x from 1 to 2 is 3/2." Same idea for cinq demi, since the integral of x from 2 to 3 is 5/2