(3/8)³ = (3/8)(3/8)(3/8)
Multiply across:
(3/8) x (3/8) = 9/64
Simplify:
(9/64)(3/8) = 27/512
27/512 is your fraction answer (cannot be reduced).
To find the decimal answer, divide:
27/512 = 0.05
0.05 (rounded) is your decimal answer
hope this helps