To add these two mixed numbers, we first need to convert them to improper fractions:

8 5/7 = (78 + 5)/7 = 61/7
5 5/3 = (35 + 5)/3 = 20/3

Now, add the improper fractions:

61/7 + 20/3 = (613 + 207)/(7*3) = 183 + 140 / 21 = 323/21

Now convert the sum back to a mixed number:

323 ÷ 21 = 15 R8

So, 323/21 = 15 8/21

Therefore, 8 5/7 + 5 5/3 = 15 8/21

Now, do the same thing for the second operation:

7 5/8 = (87 + 5)/8 = 61/8
6 5/4 = (46 + 5)/4 = 29/4

Add the improper fractions:

61/8 + 29/4 = (614 + 298)/(8*4) = 244 + 232 / 32 = 476/32

Now convert the sum back to a mixed number:

476 ÷ 32 = 14 R28

So, 476/32 = 14 28/32 = 15 20/32

Therefore, 7 5/8 + 6 5/4 = 15 20/32

I hope this helps! Let me know if you need any further assistance.