per fare le somme dentro le parentesi tonde ci vuole il minimo comune denominatore.
mcd (2 ; 30) = 30; 1/2 = 15/30; 15/30 - 1/30 = 14/30.
mcd (5; 10) = 10; 2/5 = 4/10; 4/10 - 1/10 = 3/10.
mcd (6; 3) = 6; 1/3 = 2/6; 5/6 + 2/6 = 7/6.
{[(14/30) : 7/15 + (3/10) * (7/6)] * 5/3 + 1/5} : 7/4 =
= {[14/30 * 15/7 + 7/20] * 5/3 + 1/5 } : 7/4 =
14/30 = 7/15, quindi (7/15) * (15/7) = 1
= { [1 + 7/20 ] * 5/3 + 1/5} : 7/4 =
= {27/20 * 5/3 + 1/5} : 7/4 =
= {9/4 + 1/5}: 7/4 =
= {45/20 + 4/20} : 7/4 =
= 49/20 * 4/7 =
= 7/5.
Ciao @gurshaan_singh