[(5 * 2^5 : 10 + 3^2)^7 : 5^10 - 20^2] : 3^2 =
= [(5*32 :10 + 9)^7 : 5^10 - 400] : 9 =
= [(160:10 + 9)^7 : 5^10 - 400] : 9 =
= [(16 + 9)^7 : 5^10 - 400] : 9 =
= (25^7 : 5^10 - 400) : 9 =
= [(5^2)^7 : 5^10 - 400] : 9 =
= (5^14 : 5^10 - 400) : 9 =
= (5^4 - 400) : 9 =
= (625 - 400) : 9 =
= 225 : 9 =
= 25 =
= 5^2