Answer:
5/7
Explanation:
There are a couple ways to solve this. One would be by finding the least common denominator for each one with 2/3, subtracting, and seeing what is left over. Another way is converting to decimals.
2/3=0.666666
————————-
7/8=0.875
8/9=0.88888
4/5=0.8
5/7=0.7143
They are all greater than 2/3 (0.6666666), but 5/7 is the closest, so would have the least waste.