You can’t take 8 away from 7. You have to make the top number larger than the bottom number.

You go to the next column to see if there is a 10 (ten) that you can borrow. You find that there are 3 tens (30) in that column, so you know that you will be able to borrow one of them.

When you borrow a ten, the 30 becomes a 20. You bring the 10 over to the ones column and add it on to the ones that are already there. Now you have 17 instead of 7.

437 = 400 + 20 + 17. You had to regroup the numbers so you could subtract.

Now go back and solve the problem.