\[Страница\ 40.\]
\[\boxed{\mathbf{56.}}\]
\[5 + 7 - 3 = 9\]
\[8 + 6 - 9 = 5\]
\[4 + 9 - 6 = 7\]
\[12 - 7 + 6 = 11\]
\[15 - 9 + 7 = 13\]
\[17 - 8 + 5 = 14\]
\[48 + 2 = 50\]
\[48 - 6 = 42\]
\[25 + 5 = 30\]
\[\boxed{\mathbf{57.}}\]
\[\boxed{\mathbf{58.}}\]
\[Подчеркните:\]
\[8 + x = 28\]
\[60 - x = 30\]
\[y - 14 = 24\]
\[Решим.\]
\[8 + x = 28\]
\[x = 28 - 8\]
\[x = 20.\]
\[18 + x = 28\]
\[x = 28 - 18\]
\[x = 10.\]
\[50 - x = 30\]
\[x = 50 - 30\]
\[x = 20.\]
\[60 - x = 30\]
\[x = 60 - 30\]
\[x = 30.\]
\[y - 14 = 24\]
\[y = 24 + 14\]
\[y = 38.\]
\[y - 4 = 24\]
\[y = 24 + 4\]
\[y = 28.\]