\[\boxed{\text{312.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[84\ :6\ :2 < 84\ :6 \cdot 2\]
\[14\ :2 < 14 \cdot 2\]
\[7 < 28.\]
\[45 \cdot 12 = 45 \cdot 12\]
\[540 = 540.\]
\[270 > 180 + 5\]
\[270 > 185.\]
\[28 \cdot 9 = 9 \cdot (20 + 8)\]
\[28 \cdot 9 = 9 \cdot 28\]
\[252 = 252.\ \]