Răspuns :
a+b+c+d=54
a+a+1+a+2+a+3=54
4a=54-6
4a=48
a=48:4
a=12
b=a+1=13
c=a+2=14
d=a+3=15
a+a+1+a+2+a+3=54
4a=54-6
4a=48
a=48:4
a=12
b=a+1=13
c=a+2=14
d=a+3=15