Explanation:
just multiply.
you apply a fraction to a quantity by multiplying the fraction with the quantity.
a.
2/3 of 3/4 = 2/3 × 3/4 = 6/12 = 1/2
b.
2/5 of 3/4 = 2/5 × 3/4 = 6/20 = 3/10
c.
2/5 of 4/5 = 2/5 × 4/5 = 8/25
d.
4/5 of 3/4 = 4/5 × 3/4 = 12/20 = 3/5