A Top Ten Resources Production of the Flipped Classroom: Learn the maths you need, where, when and how you want.
Renaming in the vertical algorithm
What does renaming mean? How can I use one place value to help me subtract when I don't have enough ones, or tens, or hundreds, etc?
More on how renaming in subtraction actually works:
Practice renaming while bowling: (TIP: Make sure you do your working out on paper, DON'T try to do it just in your head on the computer because it's very hard and you need to start at the ones, not the hundreds!!!): Bowling through Renaming.