\[\boxed{\mathbf{1}\mathbf{.145.ОК\ ГДЗ - домашка\ на\ }5}\]
\[\textbf{а)}\ 20 \cdot 5 = 100 - 60 = 40\ :8 =\]
\[= 5 + 25 = 30 \cdot 3 = 90\]
\[\textbf{б)}\ 25 \cdot 4 = 100\ :20 = 5 \cdot 9 =\]
\[= 45 - 15 = 30\ :6 = 5\]
\[\textbf{в)}\ 70 + 30 = 100\ :5 =\]
\[= 20 - 20 = 0 \cdot 5 = 0\]
\[\textbf{г)}\ 90 - 70 = 20 \cdot 5 = 100\ :25 =\]
\[= 4 + 26 = 30\]