4/7+(-11/14) , -4/9-5/12, -14/25×20/21, 14/9:(-16/15)

Question

4/7+(-11/14) , -4/9-5/12, -14/25×20/21, 14/9:(-16/15)

Answer 1

4/7+(-11/14)=8/14-11/14=-3/14; //// , -4/9-5/12=-16/36-15/36=31/36;//////, -14/25×20/21=-8/15; / ////// , 14/9:(-16/15)=14/9*(-15/16)=-35/24==-1 11/24