Răspuns :
d : 4 + 35 : 5 + 4 = 21
d : 4 + 7 + 4 = 21
d : 4 + 11 = 21
d : 4 = 21 - 11
d : 4 = 10
d = 10 x 4
d = 40
d : 4 + 7 + 4 = 21
d : 4 + 11 = 21
d : 4 = 21 - 11
d : 4 = 10
d = 10 x 4
d = 40