Answer:
64/80
Step-by-step explanation:
When you put in your calculator 4/5 it spits out ".8".
You are looking for another fraction that spits out 0.8.
One of the choices that gets my attention is 64. Let's test it to see if I was right first try.
Calculator: 64/80 = 0.8; 64/80 is equivalent to 4/5.