2 1/52*26/49-3 3/7:1 5/11
решение:
1) 2 1//52 * 26//49=15//14=1 1//14
2) 3 3//7 : 1 5//11=33/14=2 5//14
3) 1 1//14 - 2 5//14= -9//7 = -1 2//7
Ответ: -1 2//7