a, \(4\times5^2-81:3^2+2^{10}:2^8\)
=\(4\times25-81:9+4\)
=\(100-9+4\)
=\(95\)
b, \(\left(5^2\times36-2^5\times12\right):12\)
=\(\left(25\times36-32\times12\right):12\)
=\(\left(75\times12-32\times12\right):12\)
=\(12\times\left(75-32\right):12\)
=\(12:12\times43\)
=\(43\)