не могу решить ) :
1) 2 6/7 -2 3/4
2)5 1/2 - 4 1/3
3)2 3/4 + 3 5/6
4)4 1/3 - 3 2/5
5)7 1/5 - 3 3/15
6)4 4/9 + 4 4/15

нет

это тебе где задоли?!

1) 2 6/7 - 2 3/4 = 20/7 - 11/4 = 80/28 - 77/28 = 3/282) 5 1/2 - 4 1/3 = 11/2 - 13/3 = 33/6 - 26/6 = 7/6 = 1 1/63) 2 3/4 + 3 5/6 = 11/4 + 23/6 = 33/12 + 46/12 = 79/12 = 6 7/124) 4 1/3 - 3 2/5 = 13/3 - 17/5 = 65/15 - 51/15 = 14/155) 7 1/5 - 3 3/15 = 7 1/5 - 3 1/5 = 46) 4 4/9 + 4 4/15 = 40/9 + 64/15 = 200/45 + 192/45 = 392/45 = 8 32/45