Question

{2•5^2-[7^2-(18^2:12-9^4:3^6):2]:2^2}:2^3

Answer 1

{2*5^2-[7^2-(18^2:12-9^4:3^6):2]:2^2}:2^3=
{2*25-[49-(324:12-3^2^4:3^6):2]:4}:8=
{50-[49-(27-3^8:3^6):2]:4}:8=
{50-[49-(27-3^2):2]:4}:8=
{50-[49-(27-9):2];4}:8=
{50-[49-18:2]:4}:8= 
{50-[49-9]:4}:8=
{50-40:4}:8=
{50-10}:8=
40:8=5