297 is very close to 300, which would be easier to add to 528 because only the hundreds would change. 297 is 3 away from 300, so I can take 3 from 528, making it 525, and give the 3 to 497, making it 500. Since the 3 is still included, the total won’t change. Now we have 525 + 300. 500 + 300 = 800, with 25 more, or 825.