7/9-5/7, 5/6+1/9,17/18-11/12,3/4-2/5 помогитее

Question

7/9-5/7, 5/6+1/9,17/18-11/12,3/4-2/5 помогитее

Answer 1

7/9-5/7=(49-45)/63=4/63
5/6+1/9=(15+2)/18=17/18
17/18-11/12=(34-33)/36=1/36
3/4-2/5=(15-8)/20=7/20