\[\boxed{\text{5.532.}}\]
\[\textbf{а)}\ 285 - 213 = 72\ :9 =\]
\[= 8 + 37 = 45\ :15 = 3\]
\[\textbf{б)}\ 800\ :16 = 50 \cdot 7 =\]
\[= 350 - 206 = 144\ :12 = 12\]
\[\textbf{в)}\ 56\ :7 = 8 \cdot 3 = 24 + 33 =\]
\[= 57\ :19 = 3\]
\[\textbf{г)}\ 100 - 55 = 45\ :9 = 5 + 27 =\]
\[= 32\ :16 = 2\]