You first take 538 and put it on the top. Then you put 247 below it and do 8 minus 7 and get 1. 1 will be in the ones digit. Then do 3-4, which you can't so you have to borrow from the 5 and 5 turns into 4. 3 which turns into 13. 13-4 is 9. 9 is in the tens place. 4-2 is 2. So the answer is 291