дроби: 25/28 -18/35 ,40/63- 35/72, 22/21- 21/22, 40/143 - 41/156, 43/126- 41/135, 239/240 - 229/228

а) 25/28-18/35=125/140-72/140=53/140б) 49/63-35/72= 392/504-245/504=147/504=7/24в) 22/21-21/22=484/462-441/462=43/462г) 40/143-41/156=6240/22308-5863/22308=377/22308д) 43/126-41/135=5805/17010-5166/17010=639/17010=71/1890е) 239/240-229/288=68832/69120-54960/69120=13872/69120=289/1440