\[\boxed{\mathbf{101.}}\]
\[\textbf{а)}\ 340 + 100 = 440\]
\[570 + 100 = 670\]
\[100 + 150 = 250\]
\[280 - 100 = 180\]
\[610 - 100 = 510\]
\[830 - 100 = 730\]
\[\textbf{б)}\ 410 - 100 - 1 = 310 - 1 =\]
\[= 309\]
\[700 + 20 - 1 = 720 - 1 = 719\]
\[1000 - 100 - 1 = 900 - 1 =\]
\[= 899\]