Răspuns:
Explicație pas cu pas:
7/15 + 1/3 - 1/5 = 7/15 + 5/15 - 3/15 = 9/15 = 3/5
3/5*5/4 = 3/4
1/2 - 1/4 = 2/4 - 1/4 = 1/4
1/4 : 5/12 = 1/4*12/5 = 3/5
3/4 + 3/5 = 15/20 + 12/20 = 27/20
27/20*2/7 = 27/70