\[\boxed{\text{85}\text{.}}\]
\[12\ 801 + 3 = 12\ 804\]
\[12\ 801 - 3 = 12\ 798\]
\[12\ 801\ :3 = 4\ 267\]
\[12\ 801 \cdot 3 = 38\ 403\]
\[30\ 510 + 15 = 30\ 525\]
\[30\ 510 - 15 = 30\ 495\]
\[30\ 510\ :15 = 2\ 034\]
\[30\ 510 \cdot 15 = 457\ 650\]