Verified answer

5/6 - (3/10 + 2/5) = 5/6 - (3/10 + 4/10) = 5/6 - 7/10 = 25/30 - 21/30 = 4/30

(3/4 + 1/8) - 5/8 = (6/8 + 1/8) - 5/8 = 7/8 - 5/8 = 2/8 = 1/4