In the past, "students had this sense that math was some kind of magical black box," says Dan Meyer, a former high school math teacher studying math education at Stanford University. "That wasn't good enough."
The Common Core wants to get kids beyond rote memorization of how to do math and towards a deeper understanding of how math actually works. This has led to some problems that have gone viral on the internet as frustrated parents vent over bizarre-looking homework assignments:
The simple example the parent gives above is known as the standard algorithm — and, under Common Core, it will still be taught. But students are also supposed to learn other methods that try to make the underpinnings of the standard method more obvious.
Take the problem above, which uses a number line to show that subtraction is really about calculating the distance between two numbers. Students put the two numbers at opposite ends of the number line.
Then they travel from one number to the next to figure out the distance. It's 4 steps from 316 to 320, 100 steps from 320 to 420, 7 steps from 420 to 427.
Then they add the steps together: 4 + 100 + 7 = a distance of 111. LearnZillion, a company that creates lesson plans for teaching to the Common Core standards, has a 5-minute video explaining this technique. Here's what it's supposed to look like on another sample problem:
Multiplication, too, is explained visually. Most people learned to multiply two-digit numbers like this:
To better understand what's really happening here — technically, you're breaking 16 into (10 + 6), then adding (27 x 10) + (27 x 6) — another method students can use is the "area model."
Much of this is bound to confuse parents — particularly because in many cases their own math backgrounds aren't particularly strong, and so they can't step in and easily find the answers themselves. But math teachers say parents need to learn to help their kids by asking them more general questions that help them learn the principles behind the problem, rather than stepping in and solving the problem themselves.
More on the Common Core's approach to math here.