Observe and find the rule, fill in the brackets. (), (), ()

Observe and find the rule, fill in the brackets. (), (), ()

Divide by two
4/5÷2=2/5
2/5÷2=1/5
1/5÷2=1/10
1/10÷2=1/20
1/20÷2=1/40
1/40÷2=1/80
4 / 5, 2 / 5, 1 / 5, (1 / 10), 1 / 20, (1 / 40), (1 / 80)