8 2/7 - 3 5/7 = (8 + 2/7) - (3 + 5/7)
= 8 + 2/7 - 3 - 5/7
= 5 + 2/7 - 5/7
= 5 + (2 - 5)/7
= 5 - 3/7
= 4 4/7

Итак, 8 2/7 - 3 5/7 равно 4 4/7.