15*(1 цел +1/3 )-1/5

15 * (1 + 1/3) - 1/5 = 15 4/5
1) 1 + 1/3 = 1 1/3
2) 15 * 1 1/3 = 15 * 4/3 = 15 : 3 * 4 = 16
3) 16 - 1/5 = 15 5/5 - 1/5 = 15 4/5