\[\boxed{\text{171.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[= 1\ 450\ :50 = 29.\]
\[В\ 29\ раз.\]
\[= 75\ 000 - 30 = 74\ 970.\]
\[На\ 74\ 970.\]
\[3)\ (1\ 000 - 1)\ :9 = 999\ :9 =\]
\[= 111.\ \]
\[4)\ 10\ 000 + 9999 = 19\ 999.\]