First, let's convert all mixed numbers to improper fractions:

13-8ц 9/10 = 13 - (8*10 + 9)/10 = 13 - 89/10 = 131/10 - 89/10 = 42/10

26ц 1/2 = 26 + 1/2 = 53/2

15ц 1/5 = 15 + 1/5 = 76/5

14ц 1/5 = 14 + 1/5 = 71/5

7 = 7

3ц 3/10 = 3 + 3/10 = 33/10

8ц 1/2 = 8 + 1/2 = 17/2

Now let's substitute these values into the equation:

(42/10) + (53/2) - (76/5) - 7 + (33/10) + (17/2)

= 42/10 + 53/2 - 76/5 - 7 + 33/10 + 17/2
= (422)/(102) + 265/10 - 152/10 - 70/10 + 99/10 + 85/10
= 84/20 + 265/10 - 152/10 - 70/10 + 99/10 + 85/10
= 4.2 + 26.5 - 15.2 - 7 + 9.9 + 8.5
= 4.2 + 26.5 - 15.2 - 7 + 9.9 + 8.5
= 24.9

Therefore, the final answer is 24.9.