\[\boxed{\mathbf{161\ (161).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[a = 1,9\ :38 = 19\ :380 = 0,05;\]
\[b = 2,24 - 1,9 = 0,34;\ \ \ \]
\[c = 2,24\ :56 = 224\ :5600 =\]
\[= 0,04.\]
\[a = 4 - 2,5 = 1,5;\ \ \ \]
\[x = 1,6\ :4 = 0,4;\ \ \]
\[y = 1,6\ :32 = 16\ :320 = 0,05.\]