StriderSquirrel Given the triangle over the 10, I assume they split the 3 into a part that adds to 9 to make 10, and the remaining number is left. In other words, instead of adding in their head, they subtract in their head, adding an extra step to the addition.
stormllama Teaching base‑10, I point out that most people do this in their heads: they sprint to 5 or 10, then fine‑tune the tiny gaps. So 9 + 1 + 2 becomes 10 + 2, which is just 9 + 3.
bluepribbs8 Honestly, I used to think the whole Common Core math thing was weird, but then I realizzed I do the same thing naturally in my head when I’m adding larger numbers. It’s easier for me to figure out whatever adds up to a nice even number and then add the remainder to it rather than trying to add it all at once. But this worksheet makes it look weird. They should just teach the kids the same normal way we learned and then let them figure out whatever adds works for them, just like I did.
