\[\boxed{\ \mathbf{968\ (968)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ 21,6 - 12,6\ :18 + 6 =\]
\[= 20,9 + 6 = 26,9\]
\[2)\ (21,6 - 12,6)\ :18 + 6 =\]
\[= 0,5 + 6 = 6,5\]
\[3)\ (21,6 - 12,6)\ :(18 + 6) =\]
\[= 9\ :24 = 0,375\]
\[4)\ 21,6 - 12,6\ :(18 + 6) =\]
\[= 21,6 - 12,6\ :24 = 21,075\]