You do it the way you change any percentage to a fraction. Divide by 100% and simplify.
66 2/3%
= (66 2/3%)/(100%)
= (200/3)/100
= 200/300
= (2*100)/(3*100)
= (2/3)*(100/100)
= (2/3)*1
= 2/3
66 2/3%
= (66 2/3%)/(100%)
= (200/3)/100
= 200/300
= (2*100)/(3*100)
= (2/3)*(100/100)
= (2/3)*1
= 2/3