Quick: What’s 99 + 47?
No calculators.
It’s 146. Of course it’s 146. You know how I know that?
Because I rounded the 99 to 100… and then subtracted one from 47 to make up the difference.
I sure as hell won’t do this:
That would be a waste of time when rearranging the numbers in your head is a lot faster. That’s what’s the math teacher in the video below is trying to explain to a news reporter using the numbers 9 and 6:
9 and 6 aren’t the best numbers to use to show why this method is so powerful, I’ll give you that, but the method makes sense.
And yet, right-wing websites are flipping out over how stupid this all seems. They blame “Common Core” (which really has nothing to do with this) and rant about how it takes the teacher “almost a minute to explain a simple math problem” (emphasis theirs):
Anybody who wants to know why there’s such a revolt against Common Core standards only has to watch this video where a teacher tries to explain how kids today learn simple arithmetic. Watch how long it takes her to go from 9 + 6 to 15:
…
This video was designed as a “helpful tool” for parents. Hint: If you actually have to show parents how to add 9 + 6, you’re doing it wrong.
As usual, the bloggers have no idea what they’re complaining about. This method is incredibly useful, even if it requires a little more explanation up front, because it can scale to larger numbers down the road.
Quick: What’s 998 + 624?
No calculators.
.
.
.
.
.
.
.
.
It’s 1622. That should have taken you all of a second to solve. Just treat the numbers like 1000 and 622 and it’s so much easier.
Remember when you learned how to type? A lot of people (hi, mom!) use the “hunt and peck” method of just finding the keys they need and pushing them with a finger. But if you take a typing class, you’re taught about the home keys and how to type without even having to look at the keyboard.
For hunt-and-peckers, typing “the right way” is a lot slower at first. But if you learn how to do it, typing will become much faster for you down the road.
That’s what this method of adding is all about. Yes, it takes a “full minute” to explain it the first time around (the jargon doesn’t help)… but if kids learn it, they’ll be able to add more quickly, not to mention perform other mathematical tasks, when the numbers get larger.
Not that the “Common Core” haters care.
They have no idea that the standards suggest students learn a variety of ways to perform basic math skills, not just this one particular method. They don’t understand how students who are taught to “just add” or “memorize the answer” struggle with math later in life because they don’t know how to manipulate numbers like the teacher in the video is doing.
I know someone on Facebook who posted this video, just to complain about it. She made a comment about how math has always been tough for her, and how this method would’ve made it so much worse.
She’s wrong.
If she learned this method from a young age, math class might have been a lot easier for her. But it requires a little time understanding what’s going on for that to make sense.
That’s never going to happen if your biggest complaint about learning a useful skill is how long it takes to understand the mechanism behind it.
(By the way, I’ve written other posts defending the importance of learning this sort of “number sense” here and here.)
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