Помогите и упростите 
7 : 2 1/3 + 4 : 1 1/3

7 : 2 1/3 + 4 : 1 1/3 = 6

1) 7 : 2 1/3 = 7 : 7/3 = 7/1 * 3/7 = 3

2) 4 : 1 1/3 = 4 : 4/3 = 4/1 * 3/4 = 3

3) 3 + 3 = 6