\[\boxed{\mathbf{Вариант\ 2.}}\]
\[{\boxed{\mathbf{1.}} }{360 + 40 = 400}\]
\[Ответ:\ \ 400.\]
\[\boxed{\mathbf{2.}}\]
\[580 - 260 = 320\]
\[Ответ:\ \ 320.\]
\[\boxed{\mathbf{3.}}\]
\[560 - 350 = 210\]
\[Ответ:\ \ 210.\]
\[\boxed{\mathbf{4.}}\]
\[220 + 80 = 300\]
\[Ответ:\ \ 300.\]
\[\boxed{\mathbf{5.}}\]
\[40 + 760 = 800\]
\[Ответ:\ \ 800.\]
\[\boxed{\mathbf{6.}}\]
\[680 - 30 = 650\]
\[Ответ:\ \ на\ 650.\]
\[\boxed{\mathbf{7.}}\]
\[300 + 150 = 450\]
\[Ответ:\ \ 450.\]
\[\boxed{\mathbf{8.}}\]
\[390 + 400 = 790\]
\[Ответ:\ \ 790.\]
\[\boxed{\mathbf{9.}}\]
\[840 - 20 < 860\]
\[Ответ:\ \ « - ».\]
\[\boxed{\mathbf{10.}}\]
\[360 + 20 = 380\]
\[280 + 100 = 380\]