Jeu 1 :

Mes solutions :

231 = (5×4+1)×(10+1)
231 = 4×(9+10×5−1)−1
231 = 5×(10+9×4)+1
231 = 5×4×(10+1+1)−9
231 = 10×4×(5+1)−9
231 = (10+1)×(5×4+1)
231 = 10×(5×(4+1)−1)−9