(20 16/25+13 9/25)-(23 4/14+7 13/14).

(20 16/25+13 9/25)-(23 4/14+7 13/14) =(20 +16/25 + 13 + 9/25) - ( 23 + 4/14 + 7 + 13/14) = (33 + 16/25 + 9/25 ) - ( 30 + 4/14 +13/14) = (33 + 25/25) - ( 30 + 17/14) = 34 - ( 30 + 1 + 3/14) =34- 31 - 3/14 =3 - 3/14 =2 + 14/14 - 3/14 =2 + 11/14 = 2 11/14