This guy taught a whole course on how to quickly do math in your head faster than a calculator. Here's a short clip of it.
Or you could just use the distributive law. 11X = (10 + 1)X = 10*X + X. No tricks required.
I do this intuitively in my head. This is Common Core or "New math", which got a lot of flack for making easy math seem more complicated when you could just DO the easy math by memory. But I think this is what it is trying to teach kids-that you can group numbers differently and use different methods to arrive at the correct answer, and learn why it works.
@Moxytocin me too lol 😂
I think it’s a generational thing. In 1960s we memorized multiplication tables up to 12 x 12 and from there it wasn’t too challenging in your head to do 12 x 100 or 11 x 1000 or 10 x 1052 etc. it’s just how we were taught then . I still “impress “ younger people than me with my “amazing “ multiplication skills 😳
Btw my middle son is a high school math teacher today and I would probably flunk his classes 😂
The key point is that the way you do arithmetic on paper and the way you do arithmetic in your head are completely different. On paper, you tend to start with the units. In your head, you tend to start with the big end.
In either case, it's easy providing you have a firm grasp of the concept of numbers and an equally firm grasp of the basic multiplication tables and number bonds.
I have never heard of a school either in the UK or the US doing this correctly.
That isn't math. That's arithmetic. Math would be knowing where the numbers came from, and how they should be manipulated.
@GreatHornedOwl - Arithmetic is math. What you're describing is called proofs.
@OhioMike That is funny.
Officially, mathematics has 64 subjects, but arithmetic isn't grand enough to be one of them. It is the original name for the simple end of Number theory (which is one of the distinct subjects).
Or to put it another way, in a sense there is no such thing as mathematics. It's just an umbrella term for a whole bunch of more-or-less related stuff.
@CuddleDuncan - I don't know about where you live, but here in the U.S., we still call it math....and the name of that course is called "Secrets of Mental Math" taught by Arthur T Benjamin who is a mathematician.
@OhioMike I resemble that comment 😂
@Mike403 I watched the second video. It is exactly what I teach to my students.
@CuddleDUncan - Americans want free education, but they aren't taking education seriously enough as it is. Many of them can't add 2+2 without a calculator.
@Mike403 Arithmetic is not math. Arithmetic is a small branch of math. Saying arithmetic is math, is like saying taking blood pressure is medicine.
@GreatHornedOwl is correct. I have won a few bets off this because a lot of people assume arithmetic and math are synonymous.
@GreatHornedOwl - You just said yourself that it is a small branch of math. So I'm failing to see the argument. I never said that arithmetic is all of math. Mathematics has many branches.
@GreatHornedOwl @FunCartel - Why would a famous mathematician call it math then? I know the different branches of math. I took a minor in mathematics at school. If I would to continue taking math classes until the day I died, I would not have learned every branch there is.
Or …
@OhioMike - Arithmetic is considered to be an elementary branch of math that is learned first before those other things.
Hey all this is way past my pay grade. I’m just curious now. I like bar bets 😂
You need arithmetic to do algebra and trigonometry. You need both of those things to do calculus. You need calculus to do differential equations.
I needed some of those to get in college lol. Then after that I stayed far away 😂
Laplace Transform is a weird branch of math I had to learn that I think only engineering students need.
@Mike403 Merriam-Webster defines arithmetic as "A branch of mathematics that deals usually with the nonnegative real numbers including sometimes the transfinite cardinals and with the application of the operations of addition, subtraction, multiplication, and division to them." It seems that they and several other dictionaries disagree with both you and your "famous mathematician.
A famous mathematician would call arithmetic math because from the second grade until sometime in college, he was conditioned to call arithmetic math, and because he never bothered to think about it. BTW, the ability to do arithmetic in his head certainly isn't sufficient reason to call him a mathematician. Being famous, doesn't prove a thing.
I have a puzzle for you, but I need you to do something first. I'll give you the puzzle after you do it.
@GreatHornedOwl - How can something be a branch of math and also not have anything to do with math?
The word, "arithmetic" reminds me of my grandmother asking me about school when I was in second grade.
I don't get it. That dictionary just called it a branch of math and somehow that proves that it isn't math. I think people just like to argue even when they know they're wrong.
I'm not arguing the definition of arithmetic, I just always understood it as the very basic math you learn in elementary school which I think was said above somewhere +-×÷. It's the only time I remember specifically hearing the word "arithmetic".
