\[\boxed{\mathbf{263\ (263)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[I\ способ.\]
\[AB = 30\ см;\]
\[BC = 10\ см.\]
\[AC = AB + BC = 30 + 10 =\]
\[= 40\ см.\]
\[II\ способ.\]
\[AB = 30\ см;\]
\[BC = 10\ см.\]
\[AC = AB - BC = 30 - 10 =\]
\[= 20\ см.\]
\[Ответ:40\ см\ или\ 20\ см.\]
\[\boxed{\mathbf{263}\mathbf{\ (232)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ (35 + x) - 15 =\]
\[= 35 - 15 + x = 20 + x\]
\[2)\ (432 + b) - 265 =\]
\[= 432 - 265 + b = 167 + b\]
\[3)\ (a + 636) - 129 =\]
\[= 636 - 129 + a = 507 + a\]
\[4)\ 96 - (m + 48) =\]
\[= 96 - 48 - m = 48 - m\]
\[5)\ 516 - (216 + x) =\]
\[= 516 - 216 - x = 300 - x\]
\[6)\ 444 - (y + 58) =\]
\[= 444 - 58 - y = 386 - y\]