Как решить 7 селых 1\9 : 10 2\3 -(49 целых 1/5-47 2/5)

7 1/9 : 10 2/3 - (49 1/5 - 47 2/5) = - 1 целая 2/15

1) 49 1/5 - 47 2/5 = 48 6/5 - 47 2/5 = 1 целая 4/5
2) 7 1/9 : 10 2/3 = 64/9 : 32/3 = 64/9 * 3/32 = (2*1)/(3*1) = 2/3
3) 2/3 - 1 4/5 = - (1 4/5 - 2/3) = - (1 12/15 - 10/15) = - 1 целая 2/15

Пояснения:
7 целых 1/9 = (7*9+1)/9 = 64/9
10 целых 2/3 = (10*3+2)/3 = 32/3
2/3 = 10/15 - доп.множ. 5
4/5 = 12/15 - доп.множ. 3