Answer: 59/80
Step-by-step explanation:
1. Put each fraction over a common denominator
5 x 16 = 80
the fractions are 64/80 and 5/80
2. Subtract 5 from 64
64 - 5 = 59
3. Put 59 over 80
59/80
4. Answer: 4/5 decreased by 1/16 equals 59/80