2 1/2× ( 2/15-3 5/6)-2 3/4

Вот по действиям

1) 2/15 - 3 5/6 = 3 + 2/15 + 5/6 = 3 + 4/30 + 25/30= 3 + 29/30= 3 29/30

2) 2 1/2 * 3 29/30 = 5/2 * 119/30 = 1/2 * 119/6 = 119/12 = 9 11/12

3) 9 11/12 - 2 3/4 = 7 1/6.