4, 2:( 2^3; 1/16) với a = 2.

Lời giải:

 \(4\,.\,2:\left( {{2^3}\,.\,\frac{1}{{16}}} \right) = {2^2}\,.\,2:\frac{{{2^3}}}{{{2^4}}}\)

\( = {2^2}\,.\,2\,.\,\frac{{{2^4}}}{{{2^3}}} = {2^2}\,.\,2\,.\,2 = {2^4}\).