\[\boxed{\mathbf{Страница}\mathbf{\ 38}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\boxed{\mathbf{128}\mathbf{.}\mathbf{\ }}\]
\[(63 + 8) + 12 = 63 + (12 + 8)\]
\[28 + (16 + 481) =\]
\[= (28 + 16) + 481\]
\[\boxed{\mathbf{129}\mathbf{.}\mathbf{\ }}\]
\[42 + (68 + 50) = 42 + 68 + 50\]
\[(900 + 361) + 100 =\]
\[= 900 + 361 + 100\]
\[(16 + 31) + (12 + 18) =\]
\[= 16 + 31 + 12 + 18\]
\[\boxed{\mathbf{130}\mathbf{.}}\]
\[\boxed{\mathbf{131}\mathbf{.}\mathbf{\ }}\]
\[48\ кг + 12\ кг = 12\ кг + 48\ кг\]
\[160\ г + 90\ г + 40\ г =\]
\[= 290\ г < 300\ г\]
\[50\ мм + 150\ мм + 60\ мм =\]
\[= 260\ мм > 200\ мм\]
\[400\ см^{2} =\]
\[= 100\ см^{2} + 40\ см^{2} + 200\ см^{2} + 60\ см^{2}\]
\[\boxed{\mathbf{132}\mathbf{.}}\]
\[\mathrm{\Delta} + \gamma = \gamma + \mathrm{\Delta}\]
\[a + b = b + a\]
\[\boxdot + 150 = 150 + \boxdot\]
\[\boxed{\mathbf{133}\mathbf{.}}\]
\[(s + \bigtriangleup ) + \blacksquare = s + ( \bigtriangleup + \blacksquare)\]
\[(a + b) + c = a + (b + c)\]
\[( \boxdot + 20) + a = \boxdot + (20 + a)\]