Actually, two thirds is already simplified.
four thirds is the same as one and one third.
1 2/3, or, in words, one and two-thirds.
5 and two-thirds
you can't reduce two thirds. 2 and 3 are both prime
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.
.333.... Simplified, it is .33
Seven thirds = 21/3
2/3 is already simplified.