3-(1/2 +1/7) = 3 - ( 7/14 + 2/14) = 3 - 9/14 = 2целых14/14 - 9/14 = 2целых5/14
2-(11/19+15/38) = 2 - ( 22/38+15/38) = 2 - 37/38 = 1целых38/38 - 37/38 = 1целая1/38
7-(19/40 + 1/3) = 7 - ( 57/120 +40/120) = 7 - 97/120 = 6целых120/120 - 97/120 = 6целых23/120
n+1/3=3/8
n=3/8 - 1/3
n=9/24 - 8/24
n = 1/24
m+1/4=2/3
m = 2/3 - 1/4
m = 8/12-3/12
m = 5/12
2/13 + m =3/5
m = 3/5 - 2/13
m = 39/65 - 10/65
m = 29/65