\[\boxed{\mathbf{97.}}\]
\[\textbf{а)}\ 419 + 1 = 420\]
\[1 + 354 = 355\]
\[200 + 60 = 260\]
\[700 - 1 = 699\]
\[540 - 1 = 539\]
\[680 - 100 = 580\]
\[\textbf{б)}\ 30 + 500 - 1 = 530 - 1 =\]
\[= 529\]
\[1 + 999 - 100 = 1000 - 100 =\]
\[= 900\]
\[700 + 2 - 0 = 702\]