Jeu 1 :

Mes solutions :

777 = 7×(100×3−9×(25−4))
777 = (100−9×7)×(25−4)
777 = 7×(9×4+25×3)
777 = 9×(25+7×4)+100×3
777 = 7×(100+9×4−25)
777 = 9×(100+7+4−25)+3