\[\boxed{\mathbf{99.}}\]
\[253 \approx 250\]
\[168 \approx 170\]
\[537 \approx 540\]
\[481 \approx 480\]
\[352 \approx 350\]
\[815 \approx 820\]
\[249 \approx 250\]
\[774 \approx 770\]