\[\boxed{Страница\ 15.}\]
\[\boxed{\mathbf{1.}}\]
\[1.\ \]
\[Неравенства,\ решением\ \]
\[которых\ является\ число\ 8:\]
\[k > 3\]
\[8 \cdot a > 11\]
\[48\ :b + 7 > 9\]
\[2.\]
\[\textbf{а)}\ a > 5\]
\[a = \left\{ 6;7;8;9;\ldots \right\}.\]
\[\textbf{б)}\ b < 3\]
\[b = \left\{ 0;1;2 \right\}.\]
\[3.\]
\[\textbf{а)}\ 234\ 096 + 457\ 806 = 691\ 902\]
\[\textbf{б)}\ 400\ 562 - 95\ 875 = 304\ 687\]
\[\textbf{в)}\ 509 \cdot 300 = 509 \cdot 3 \cdot 100 =\]
\[= 1527 \cdot 100 = 152\ 700\]
\[\textbf{г)}\ 7120 \cdot 807 = 5745840\]
\[4.\]
\[x > 3\]
\[x = \left\{ 4;5;6;\ldots \right\}.\]
\[y < 6\]
\[y = \left\{ 0;1;2;3;4;5 \right\}.\]
\[5 \cdot x < 16\]
\[x = \left\{ 0;1;2;3 \right\}.\]
\[8 - y > 6\]
\[y = \left\{ 0;1 \right\}.\]
\[\boxed{\mathbf{2.}}\]
\[1.\]
\[Неравенства,\ решением\ \]
\[которых\ является\ число\ 11:\]
\[x < 13\]
\[y > 9\]
\[2.\]
\[\textbf{а)}\ x > 4\]
\[x = \left\{ 5;6;7;\ldots \right\}.\]
\[\textbf{б)}\ y < 2\]
\[y = \left\{ 0;1 \right\}.\]
\[3.\ \]
\[\textbf{а)}\ 613\ 207 + 409\ 345 =\]
\[= 1\ 022\ 552\]
\[\textbf{б)}\ 120\ 040 - 89\ 768 = 30272\]
\[\textbf{в)}\ 308 \cdot 400 = 308 \cdot 4 \cdot 100 =\]
\[= 1232 \cdot 100 = 123\ 200\]
\[\textbf{г)}\ 8250 \cdot 906 = 7474500\]