nine fifteenths simplified
two thirds is greater because 0.6=three fifths so three fifths and two thirds could be simplified into nine fifteenths and two thirds could be simplified into ten fifteenths so ten is greater than nine so it is two thirds.
Nine tenths minus eight fifteenths equals eleven thirtieths.
Two fifths = six fifteenths, two thirds = ten fifteenths...
They are equivalent.
Eleven fifteenths minus ten fifteenths is equal to one fifteenth.