\[\boxed{\mathbf{14}\mathbf{.}}\]
\[\textbf{а)}\ 40 + 13 - 1 = 53 - 1 = 52\]
\[5 + 24 - 2 = 29 - 2 = 27\]
\[67 - 4 - 12 = 63 - 12 = 51\]
\[56 - (18 + 2) = 56 - 20 = 36\]
\[37 + (11 - 9) = 37 + 2 = 39\]
\[52 - (7 + 5) = 52 - 12 = 40\]
\[\textbf{б)}\ 72 - (45 + 6) = 72 - 51 =\]
\[= 21\]
\[14 + (90 - 4) = 14 + 86 = 100\]
\[81 - (5 + 27) = 81 - 32 = 49\]