7° tarefa: "Os quatro quatros"

11: 44/√4.4 = 44/√16 = 44/4 = 11

12: (44+4)/4 = 48/4 = 12

 
13: 44/4 + √4 = 11+2 = 13

14: 4+4+4+√4 = 4+4+4+2 = 14

15: (44/4)+4 = 11+4 = 15