#### Answer

Estimate: 100,000; Exact: 101,802

#### Work Step by Step

To find how many more Union deaths than Confederate deaths there were, we add Union deaths together, then add Confederate deaths together, then subtract them. Using rounded numbers to estimate, we get 100,000 + 300,00 = 400,000 Union deaths, 100,000 + 200,000 = 300,000 Confederate deaths, and finally 400,000 - 300,000 = 100,000 more Union than Confederate deaths. Using the actual numbers to find the exact answer, we get 110,070 + 250,152 = 360,222 Union deaths, 94,120 + 164,300 = 258,420 Confederate deaths, and finally 360,222 - 258,420 = 101,802 more Union than Confederate deaths.