2^21 : [(3^3 * 5 : 15 + 7^0)^5 : 10^3 - 6^2]^3 + 79 =
= 2^21 : [(3^2 * 3 * 5 : 15 + 1)^5 : 10^3 - 36]^3 + 79 =
= 2^21 : [(9 + 1)^5 : 10^3 - 36]^3 + 79 =
= 2^21 : (10^5 : 10^3 - 36)^3 + 79 =
= 2^21 : (100 - 36)^3 + 79 =
= 2^21 : 64^3 + 79 =
= 2^21 : (2^6)^3 + 79 =
= 2^21 : 2^18 + 79 =
= 2^3 + 79 =
= 8 + 79 =
= 87