Solution - Simplification or other simple results

Step  1  :

 1.1     16 = 24

(16)² = (2⁴)² = 2⁸

Equation at the end of step  1  :

  (202) +  28

Step  2  :

 2.1     20 = 22•5

(20)² = (2²•5)² = 2⁴ • 5²

Equation at the end of step  2  :

  (24•52) +  28

Step  3  :

Final result :

  656