Estimate 317 and 289 miles

I would estimate it was approximately 600 miles altogether. Since 317 is slightly more than 300 miles, we can round it down and use 300 as an approximation for that number. Since 289 is slightly less than 300, we can round that one up to 300 as an estimate. When you add 300 and 300, you get 600. This can be used as a ballpark figure for the the answer of 317 + 289 miles because we used a close benchmark for each number and added those together.