how much is 3/5 of 2/3? well, it's just their product, thus
[tex]\bf \cfrac{3}{5}\cdot \cfrac{2}{3}\implies \cfrac{3}{3}\cdot \cfrac{2}{5}\implies 1\cdot \cfrac{2}{5}\implies \cfrac{2}{5}[/tex]
now, bearing in mind that 3/3 is just 1 whole, and we can express it as 5/5 as well, so 3/5 of 2/3 of a whole is just 2/5 of the whole.
check the picture below.
