Calculeaza a,b,c apoi sumele a + b, c + a, a + b + c, unde
a = 1 / 4 + 1 / 6 + 1 / 8
b = 1 / 20 + 1 / 40 + 1 / 50
c = 1 / 20 + 1 / 12 + 1 / 24