x-nr de mere
x/2 +1/2= (x+1)/2 -cat primeste primul
x-(x+1)/2= (2x-x-1)/2= (x-1)/2 -restul
(x-1)/2 /2 +1/2= (x-1)/2 *1/2 +1/2= (x-1)/4 +1/2= (x-1)/4 +2/4= (x-1+2)/4= (x+1)/4-primeste al 2lea
(x-1)/2- (x+1)/4= (2x-2)/4 - (x+1)/4= (2x-2-x-1)/4= (x-3)/4-restul
(x-3)/4/2 +1/2= (x-3)/4 *1/2 +1/2= (x-3)/8 + 4/8= (x-3+4)/8= (x+1)/8- al 3lea copil
(x+1)/2 +(x+1)/4 + (x+1)/8 =x aducem la acelasi numitor
4x+4 +2x+2 +x+1 =8x
7x+7=8x
7x-8x=-7
-x=-7
x=7