\[\boxed{\mathbf{33.}}\]
\[\textbf{а)}\ 30 + 20 = 50\]
\[30 + 2 = 32\]
\[32 + 10 = 42\]
\[32 + 4 = 36\]
\[40 + 30 = 70\]
\[40 + 5 = 45\]
\[45 + 10 = 55\]
\[45 + 3 = 48\]
\[\textbf{б)}\ 30 + 70 = 100\]
\[3 + 70 = 73\]
\[73 + 10 = 83\]
\[73 + 6 = 79\]
\[50 + 20 + 6 = 70 + 6 = 76\]
\[30 + 0 + 8 = 38\]
\[64 + 5 + 0 = 69\]
\[0 + 4 + 40 = 44\]