Here’s a great video by Vox, the news website that’s all about the bottom line reality of issues in the news. In other words, the video is not from an advocacy group. And it shows in 3 minutes and 11 seconds why the Common Core standards want our second graders to understand more about subtraction than “borrow the one.”
h/t Wes Farno
Advancing New Hampshire Public Education 
But can they do this in cursive:-) Seriously, teaching student how to think about math instead of just following algorithms will ensure that they might have the math skills to avoid getting replaced by a computer in the workforce.