Firstly, we must convert 80% to 80/100
80%= 80/100
Next, we must divide each number by 10.
(80÷10)/(100/10)
8/10
Then, look for the greates common factor
Factors of 8:
1, 8
2, 4
Factors of 10:
1, 10
2, 5
The GCF is 2
Divide each side by 2
(8÷2)/(10/2)
The answer is 4/5